The smoke from the huge charcoal grill curls against the early-evening sky. Buffet tables are heaped with steaming corn fresh from a neighboring field and steaks just off the grill.

At surrounding tables are diners who have filled up at the groaning board or brought their own, and now sit amid the roses and trees of Wye Mills Gardens, enjoying the view of the Australian black and whistling swans, snow geese and ducks on the ponds. Peacocks, roosters, sheep and ponies parade about, set off against the green border of soybean fields.

It's all part of the package at the Eastern Shore's Wye Mills Theater -- a dinner theater or, more aptly a picnic playhouse that sets the stage with one more distinctive pleasure: You can sail up the Wye East River for a show, and the theater's launch will bring you ashore.

The theater's two-month summer run began with the musical "Barnum," which runs through July 16, and follows with "On Golden Pond," the Broadway play that became the 1981 hit movie (July 19 to August 6), and "Talley's Folley," a two-character drama that won the Pulitzer Prize in 1980 (August 9 to 27).

Joan and Dan Kramer founded the theater on their hundred-acre farm in 1976, holding performances in a giant tent. Two years later, they built a 300-seat playhouse, open to breezes from the river a quarter- mile away but screened from the low-lying Eastern Shore's insects.

The idea of the theater blossomed while Joan Kramer was studying speech and drama with the Rev. Gilbert Hartke at Catholic University, and Dan was running a landscaping and nursery business. At first it was a family affair; now there's a professional staff and director, but three of the six Kramer children are still part of the nonprofit operation. Joan serves as artistic managing director and Dan as executive producer.

The theater, about 40 miles east of the Beltway in an area rich with sightseeing opportunities, is an easy trip by car or boat. Nearby Wye Landing on the Wye East River is a lovely afternoon's sail or cruise from Annapolis or Galesville. And heading to the theater by boat gives you an entirely different perspective on the Eastern Shore.

As you round the bend of the Wye East above Shaw Bay, for example, the imposing Wye House comes into view. The grand manor house, rebuilt in 1781 after the Revolution, stands on the shore of Lloyd's Creek, named for one of the handful of families who owned half of the Shore in the mid- 18th century. Wye Heights, another mansion built by the Lloyds, stands on a bluff farther up, where the Wye East meets Wye Narrows and Skipton Creek. Neither mansion is viewable from the road or open to the public.

If you're driving, you can drop by the Old Wye Mill and the Wye Oak. The mill, which ground flour for Continental troops in the Revolutionary War, stands as it did in Washington's time, although the water wheel was replaced in 1919. The mill, closed for repairs, is still a scenic side trip.

So is the great Wye Oak, more than 400 years old and more than 95 feet high, with a crown spread of 165 feet, which inspired Maryland to adopt the white oak as its state tree.

Just beyond is Old Wye Church, built in 1721 on the foundation of a much earlier structure. It was restored in the late 1940s by the architect who directed the work at Bruton Parish Church in Williamsburg. And nearby Easton, St. Michaels, Royal Oak and Oxford offer plenty of sightseeing opportunities and overnight accommmodations. GETTING THERE BY LAND WYE MILLS THEATER -- From the Beltway, take U.S. 50 about 15 miles past the Bay Bridge and turn right onto Maryland Route 404. Wye Mills Theater is less than a mile from the intersection. Tickets for dinner and performance are $18 Monday through Friday and $19 on Saturday. Tickets for the performance only are $9, Monday through Friday, $9.50 on Saturday and $6.75 for the Saturday matinee that's presented once during each play's run. Wine, beer and mixed drinks are available. If you come by boat, bus transportation from the shore is $1 per person. For additional information about the theater or to order tickets, call 301/827- 8848 or write Wye Mills Theater, PO Box 246, Wye Mills, Maryland 21679. OLD WYE MILL AND WYE OAK -- From the theater, continue on about halfa a mile to the intersection of Routes 404 and 662. BY SEA Sharp-Adams, a booking service in Annapolis, can arrange a charter sail to Wye Landing on a bareboat, if you're a qualified sailor, or on a craft with a captain, if you prefer total relaxation. Overnight can be spent either on the boat or ashore at one of its bed- and-breakfast listings. Boat charters can also be arranged through firms in Annapolis and Galesville. Prices vary considerably according to the size of the boat and whether a captain goes with it. Charter firms include: ANNAPOLIS BAY CHARTERS -- 301/261-1815. BRETON BAY YACHTS -- Annapolis. 301/261-1018. C&C CHARTERS -- Annapolis. 1/800/638-0426 or 301/757-0707. CHESAPEAKE AND COASTAL CHARTERS -- Annapolis. 301/261-1410). DOCKSIDE CHARTER SERVICES -- Annapolis. 301/261- 2039. HARTGE CHESEAPEAKE CHARTERS -- Galesville. 301/261-9040. SUN & SEA YACHT CHARTERS -- Annapolis. 301/858- 5651. STAYING THERE Here are some accommodations if you decide to stay overnight: TIDEWATER INN -- Easton. Double rooms are $48 to $54 per night (301/822-1300). INN AT PERRY CABIN -- St. Michaels. Overlooking the Miles River. Double rooms $80 to $120, including a continental breakfast. 301/745-5178. MARTINGHAM HARBOUR TOWNE INN -- St. Michaels. $55 for weekend double room. 301/745- 9066. ST. MICHAELS MOTOR INN -- $48 for a weekend double room. 301/745-3333 or 301/822-8660. SMITHSON INN -- St. Michaels. Weekend rates $45 to $65 for Continental breakfast and double room 301/745-5793..PASADENA INN -- Royal Oak. $70 for double room and two meals for two people. 301/745-5053. ROBERT MORRIS INN -- Oxford. Overlooking the Tred Avon River. Double rooms $30-100. 301/226- 5111. SHARP-ADAMS -- This service can reserve a room for you at the Pasadena Inn, the Smithson Inn, a 19th- century manor house with a butler near Easton, a waterman's cottage in Oxford or other privately owned homes or yachts moored on the Eastern Shore. $38-$70 a night. 301/269-6232).