When deciding just what to do with precious vacation time, some get by with a little help from their friends; others look to organizations focused on a particular demographic, diversion or location to put together the perfect trip. Below are resources for some of the more popular specialty travel topics. If you can't figure out which of your interests to indulge on your upcoming travels, check out Specialty Travel Index (888-624-4030,www.specialtytravel.com), a magazine and accompanying Web site with plenty of ideas.
* Appalachian Mountain Club, 800-411-5776, www.outdoors.org. Hike through the Appalachian region with the oldest recreation group in the United States. Excellent workshops and family outing suggestions on its Web site.
* Away.com, www.away.com. Extensive site that features Top 10 lists of places, activities and adventures, and highlights travel deals. Also, great photography (including a "Behind the Image" section) and feature stories. The same company runs Outsideonline.com (the site for Outside Magazine) and GORP Travel (www.gorptravel.com), a guide and reservation service that also includes destination reviews and "best of" lists.
* iExplore.com, 800-439-7567, www.iexplore.com. National Geographic invested in this adventure and experiential travel agency that offers trips around the world, from the Taj Mahal to the Galapagos.
* National Outdoors Leadership School, 800-710-6657, www.nols.edu. Pricey wilderness trips that are great for developing mountaineering and backcountry survival skills. Undergrads at more than 400 colleges can receive college credit for semester courses, but you don't have to be a student to get schooled in the wild.
* Sierra Club, 415-977-5522, www.sierraclub.org/outings. The environmental group offers more than 350 volunteer-led trips worldwide, including volunteer vacations.
* Trails.com, www.trails.com. Descriptions and maps of 30,000 trails can be accessed for free at this all-trails-all- the-time site. The Topo Finder lets you search for topographical maps anywhere in the United States. Annual membership for full benefits is $49.95.
* Wilderness Travel, 800-368-2794, www.wildernesstravel.com. Offers intense, expert-led -- and expensive -- cultural, trekking, archaeological and oceanic expeditions worldwide, from Timbuktu to Patagonia.
* Audubon Naturalist Society, 301-652-9188, Ext. 11, www.audubonnaturalist.org. The local preservation group's Travel Program offers trips to observe the outdoor world.
* Better World Club, 866-304-7540, www.betterworldclub.com. Organization that touts itself as more socially responsible than AAA offers roadside assistance and eco-friendly car rental discounts. Its travel service charges $35 for inquiries. Basic membership is $53.95 a year.
* Conservation International's Ecotravel Center, 800-406-2306, www.ecotour.org. Check the Web site for profiles of biodiversity spots and information on in-country eco-friendly agencies (it doesn't offer itineraries or travel-planning assistance).
* Green Hotels Association, 713-789-8889, www.greenhotels.com. Its Web site shows eco-conscious hotels arranged by state.
* International Ecotourism Society, 202-347-9203, Ext. 275, www.ecotourism.org. Ask ecotourism questions of organization members or become a member for $35 and use the Web site to find tour operators, eco-friendly lodging and specialized info by region.
* National Audubon Society, 800-967- 7425, www.audubon.org. The world- wide natural-history-focused "Nature Odysseys" work with companies that adhere to the society's eco-sensitive travel ethics.
* National Park Service, 888-467-2757, www.nationalparks.org. A site for anything and everything to do with traveling to national parks. Recreation.gov offers information on wildlife watching, hunting/fishing permits and information on Federal Recreation Pass programs, like the Golden Age Passport, which includes admission to national parks and discounts for those 62 and older; $10 for a lifetime pass.
* Nature Conservancy, 800-633-4734 , www.nature.org/aboutus/travel. Its "Conservation Journeys" division partners with eco-tour companies in some of the world's "Last Great Places" and highlights a few destinations annually (this year it's partnered with International Expeditions for trips to the Calakmul Biosphere Reserve and Honduras).
* Interhostel, 800-733-9753, www.learn.unh.edu/interhostel. The University of New Hampshire-sponsored trips mix lectures and excursions for travelers over age 50.
* Lingua Service Worldwide, 800-394- 5327, www.linguaserviceworldwide.com. The independent agency represents schools for 10 languages with intensive programs in about 15 countries. Prices are listed in dollars for easy comparisons.
* Shaw Guides, 212-799-6464, www.shawguides.com. A comprehensive source with more than 5,700 listings for cultural, art, photography, language and cooking vacations, with links to more complete info.
* Smithsonian Journeys, 877-338-8687, www.smithsonianjourneys.org. Premier (and expensive) worldwide educational programs organized by the venerable Smithsonian, including trips based on Smithsonian magazine stories. Members only, but the $29-per-household fee can be applied to your trip.
* Study Abroad.com, 610-499-9200, www.studyabroad.com. Listings shouldn't be taken as endorsements, but the site is a good resource for undergrads looking for different study abroad options, with separate categories for non-students and those 55 and older.
* Family-Reunion.com, www.family-reunion.com. "Mister Spiffy" offers hints on good reunion locations, organizational tips, entertainment suggestions and geneology guidelines, all with a sense of humor.
* FamilyFun.com, www.familyfun.com/travel. Disney-produced Web site with many non-Disney vacation ideas, plus travel checklists and tips for those with tweens.
* Family Travel Files, www.thefamilytravelfiles.com. Special features include a Vacation Ideas Directory (organized geographically) and a list of special events and festivals organized by state.
* Family Travel Forum, 212-665-6124, www.familytravelforum.com. Membership-based online newsletter that lists family-friendly travel agents and tips, like documents a parent needs to travel solo with the kids. $38 annual membership.
* Family Travel Network, 703-905-9858, www.familytravelnetwork.com. The site is packed with vacation deals, plus tips on warm-weather holiday destinations and links to family-friendly travel agents -- and it's free.
* Damron, 800-462-6654, www.damron.com. Damron publishes five travel and accommodation guides and offers a $31.95 per year online database of 15,000 gay-friendly and gay-owned establishments.
* GayRes.com, www.gayres.com. This gay-owned company specializes in discounts for budget and luxury gay-friendly accom- modations worldwide.
* GayTravel.com, 800-429-8728, www.gaytravel.com. Gay-friendly vacation booking service, with an active travel forum.
* International Gay and Lesbian Travel Association, 800-448-8550, www.iglta.com. Trade association promoting gay tourism. Search the site for gay-owned and gay-friendly accommodation booking services, independent B&Bs and travel agencies.
* Out and About, www.outandabout.com. The company offers a comprehensive monthly newsletter and publishes travel guides. Check out the Editor's Choice Awards for the year's best (and worst) companies and destinations for gay men and lesbians.
* Travel Alternatives Group, 415-437- 3800, www.gaytravelnews.com. Organization that certifies travel agents and tour outlets as gay-friendly.
* Access-Able Travel, 303-232-2979, www.access-able.com. Comprehensive site of travel agencies, tours, cruises and travel tips for mature travelers and those with special needs.
* Centers for Disease Control and Prevention, 877-394-8747, www.cdc.gov/travel. Indispensable site for travel info on disease prevention from the U.S. Department of Health, listing travel medicine clinics, vaccinations and more.
* Emerging Horizons, 209-599-9409, www.emerginghorizons.com. Magazine and Web site for people with mobility disorders, including slow walkers. Extensive travel resources include accessibility info for various destinations and a Q&A column. Annual subscriptions are $14.95.
* Global Dialysis, www.globaldialysis.com. Listings of 11,800 dialysis centers in 127 countries as well as travel agents who specialize in working with dialysis patients.
* International Association for Medical Assistance to Travellers, 716-754-4883, www.iamat.org. Web site lists recent health-related articles on such topics as avian influenza outbreaks. Free membership offers access to worldwide listings of English- speaking doctors with medical training in the United States, Canada or Great Britain who charge a set fee for initial consultations.
* Medical Travel Inc., 800-778-7953, www.medicaltravel.org. Travel agency sets up vacations for dialysis and oxygen patients. Arranges for such rental equipment as golf carts and oxygen tanks.
* MedicAlert, 888-633-4298, www.medicalert.org. Worldwide emergency medical info service. Members wear a special bracelet or necklace engraved with an ID number that is linked to medical history. Membership is $35 for the first year, $20 annual renewal fee.
* Mobility International USA, 541-343- 1284, www.miusa.org. MI's mission is to include the disabled in global exchange programs.
* Society for Accessible Travel and Hospitality, 212-447-7284, www.sath.org. Advocacy group represents disabled travelers and maintains lists of tour operators; its Web site offers a list of disabled-travel organizations.
* Travel O2, 888-467-3563, www.travelo2.com. Specializes in info and rentals for travelers who depend on special oxygen supplies.
* Animal and Plant Health Inspection Service, 866-723-4827, www.aphis.usda.gov/travel. The official word from the U.S. Department of Agriculture on what to do when traveling with pets.
* Hike With Your Dog.com, www.hikewithyourdog.com. Search for dog-friendly hikes by state. Other screens suggest relevant books and give advice on traveling with dogs. Also offers "Hike With Your Dog" tours of the mid-Atlantic region and notes that the top two beaches in the United States (ranked by "Dr. Beach") are dog-friendly.
* Pet Friendly Travel.com, www.petfriendlytravel.com. Lodging listings in the United States and Canada focus on condos, cabins and private homes that allow pets. Listings provide info on local activities and special pet-friendly amenities.
* Pet Travel.com, 954-684-9535, www.pettravel.com. Worldwide lodging info with 28,690 listings. Also, comprehensive info on immigration laws and airline policies.
* Pets Welcome.com, 845-297-5150, www.petswelcome.com. Excellent listings on a variety of pet-friendly lodgings, info on international travel and tips on dealing with emergencies. The "Search by Route" feature allows you to see pet-friendly lodging on your way to your final destination.
* AARP, 888-687-2277, www.aarp.org/travel. Popular advocacy group offers travel discounts among its other services. Membership (50 and older only) is $12.50 a year.
* Elderhostel, 877-426-8056, www.elderhostel.org. Nonprofit group organizes adventures for almost a quarter-million travelers over 55 each year. Take the grandkids on one of the Intergenerational programs or check out the associated Road Scholar program at www.roadscholar.org.
* Grand Circle Travel, 800-553-1129, www.gct.com. This company markets tours and cruises specifically to the over-50 set (but anyone over 13 is welcome) and efforts are made to limit single supplements for solo travelers. The Overseas Adventure Travel division offers trips a bit bolder than those under the Travel division.
* Hostelling International USA, 202- 783-6161, www.hiusa.org. This site covers low-cost lodging in the United States, with links to hostel information in more than 60 countries available to people of all ages. Membership for those 55 and over is $18 a year (normally $28 a year) and includes international travel insurance coverage and Greyhound discounts.
* National Active and Retired Federal Employees Association, 800-627-3394, www.narfe.org. Group that includes federal retirees and their families offers travel discounts among its perks. Membership is $33 annually after retirement.
* Senior Summer School, 800-847- 2466, www.seniorsummerschool.com. Mostly two- to six-week summer educational programs with classes in political science, art, etc. The sessions are at eight locations in the United States and Canada.
* Connecting: Solo Travel Network, 800-557-1757, www.cstn.org. Helps solo travelers find compatible travel partners through a bimonthly newsletter and offers tips on avoiding single supplements. Annual membership is $30.
* Going Solo Travel Club, 800-475-3755, www.goingsolotravel.com. Offers international tours for single travelers and matches travelers with roommates to avoid single supplements. No membership fees.
* O Solo Mio Singles Tours, 800-959- 8568, www.osolomio.com. Travel club of group trips for individuals, about 75 percent of whom are women. It aims to arrange roommates for those who want them, but it's not guaranteed.
* Singles Travel International, 877-765-6874, www.singlestravelintl.com. Agency guarantees you a roommate on its singles-only trips or it will pay the single supplement.
* Solo Dining.com, 800-299-1079, www.solodining.com. Tips and strategies for dining alone, plus an online newsletter with advice on tipping and how to avoid getting a bad table.
* Solo Tourist.com, www.solotourist.com. This site has lots of advertisements, but it also lets you create your own travel blog and offers an extensive resources list.
* Travel Alone and Love It.com, www.travelaloneandloveit.com. This free Web-only newsletter, penned by a flight attendant, has a helpful Q&A page and numerous links to other Web sites.
* Travel Chums, 212-787-2621, www.travelchums.com. This Shaw Guides-related service offers free membership to contact travelers or place ads for travel companions.
* Green Earth Travel, 888-246-8343, www.vegtravel.com. Vegetarian and eco-specialist local travel agency that also focuses on working with non-profit organizations.
* Happy Cow's Global Guide to Vegetarian Restaurants, www.happycow.net. Lists meat-free restaurants and health food stores worldwide. There's also a "vegetarian singles" forum.
* Shamash: The Jewish Network, www.shamash.org/kosher. Searchable database of 1,800 kosher restaurants in 40 countries. The site does not vouch for the accuracy of info, so ask the establishment for its kashrut certification to make sure.
* Travel Organic.com, www.travelorganic.com. A free guide to restaurants and stores offering organic goods and services around the globe, such as 11 organic bakeries, five markets and 19 restaurants in Paris.
* Vegetarian Resource Group, 410- 366-8343, www.vrg.org. Publishes books on vegetarian travel, lists vegetarian food festivals and links to VegDining.com (www.vegdining.com), which lists veggie restaurants worldwide.
* American Hiking Society, 800-972- 8608, www.americanhiking.org. One- and two-week trips to preserve U.S. trails while camping. You supply the camping equipment, work six to eight hours daily and help with chores. Trips cost $120.
* Amizade, 888-973-4443, www.amizade.org. Both short- and long-term community service projects in 11 countries in Africa, Asia, Australia, Europe, South America and the United States. Trips range from $560 at a Montana ranch to almost $2,700 in Bolivia.
* Cross Cultural Solutions, 800-380- 4777, www.crossculturalsolutions.org. Two- to 12-week humanitarian trips in 10 countries, including China, Brazil and Russia, with the specific task tailored to your skills and interest. Fees ($2,389 to $4,996) include all in-country expenses.
* Earthwatch Institute, 800-776-0188, www.earthwatch.org. No experience necessary to collect data alongside scientists on archaeological digs and wildlife studies in 47 countries. Trips usually range from one to two weeks, $700 to $4,000.
* Earth Island Institute's Global Service Corps, 415-788-3666, Ext. 128, www.globalservicecorps.org. Volunteers participate in educational, health care, sustainable agriculture and HIV/AIDS programs in Thailand and Tanzania. Costs start at about $2,100 for two weeks.
* Explorations in Travel, 802-257-0152, www.volunteertravel.com. Short-term individual placements with ecological, conservation and wildlife projects in Ecuador, Puerto Rico, New Zealand and other locations. $775 to $975 for the placement; volunteers responsible for their expenses.
* Global Volunteers, 800-487-1074, www.globalvolunteers.org. Volunteers work in the United States and abroad on projects determined by locals to be most important, such as job skills or health care. Most volunteers for the one- to three-week programs are 50- to 80-years-old. Costs $750 to $2,900.
* Habitat for Humanity's Global Village Program, 800-422-4828, www.habitat.org/GV. Short-term house-building projects in 100 countries. Costs $1,200 to $4,000.
* Health Volunteers Overseas, 202- 296-0928, www.hvousa.org. Health- related teaching programs for seasoned medical professionals in more than 25 countries. Assignments are one week to two months. Volunteers cover their expenses.
* International Volunteer Programs Association, www.volunteerinternational.org. Links to organizations with volunteer exchange programs that suit your interest or destination.
* Passport in Time, 800-281-9176, www.passportintime.com. Archaeological and historic preservation programs by the USDA Forest Service. No fee to participate, but you often must provide your own transportation, food and lodging.
* Wilderness Volunteers, 928-556- 0038, www.wildernessvolunteers.org. Weeklong projects on U.S. public lands, where you'll maintain trails and prevent erosion. Most trips are under $200 a week. Camping gear is not supplied. A complete 2006 trip schedule will be posted in December.