INTERSTATE 95 and 64 through Central and Southeastern Virginia could easily be nicknamed "Amusement Alley." In a space stretching from 75 miles south of Washington to five miles the other side of Williamsburg are two giant "theme parks," a la Disneyland. Throw in visits to Colonial Williamsburg or the nearby Virginia Beach area and you have enough entertainment for a week.

The Busch Gardens and King's Dominion parks are each built around a certain topic, are expensive, draw huge crowds, provide essentially the same type of attractions and can easily consume a full day. Both present special entertainment throughout the day. Each offers, for $1 at King's Dominion and free at Busch Gardens, a kennel for those people who would take pets on a weekend outing.

Both have carnival rides and count as the most popular the "log flumes" which carry passengers roller-coaster-style down a water course. Even the elaborate carousels at the two parks appear nearly identical.

We visited both on a recent weekend and our impression of the two boils down to this: King's Dominion, at Doswell, Va., is closer and accepts crowds more easily, but Busch Gardens is more attractive, with a more mature theme. Both should be a great deal of fun for children but may require something close to a second mortgage for a large family.

Busch, open 9:30 a.m. to 10 p.m., is five miles southeast of Williamsburg and charges $8 for each person 4 years old and older. King's Dominion, 10 a.m. to 10 p.m., charges $8.50 per person 3 years old and older. Each charges an additional $1 for parking. Busch offers a $5.50 ticket for persons arriving after 5 p.m. and a $10 ticket for those also wishing to return the next day. King's Dominion's two-day ticket for the same period costs $12.50.

We began our tour of the two parks with big mistakes. Our first was choosing a Sunday in the middle of the Memorial Day weekend. The second was deciding to get to Busch Gardens early, at the 9:30 opening time.

We waited for half an hour in a line of cars, waited another 15 minutes for a double-decker London Transport bus to take us to the main entrance, and more than half an hour in line just to buy a ticket to get inside the park. After another 10 minutes in line we were able to get on the train to go from one half of the park to the other.

But to be fair, we had chosen the worst hour of the heaviest day in the history of Busch Gardens at Williamsburg, according to a spokesman. The park came close to closing its gates for a few hours, he said, because nearly 22,000 persons were jammed into the 380-acre park by mid-afternoon. Since its theme is the "Old Country," meaning primarily the Medieval days of Europe, its streets blend into shops and form narrow passageways inconvenient for large crowds.

Because of the theme and its dedication to preserving the surrounding woodlands, Busch Gardens could be more crowded with the same number of people in nearly the same acreage than King's Dominion, which drew about 20,000 persons on the same day, a normal Sunday crowd, in 320 acres.

But Busch Gardens is more attractive than King's Dominion. It was immaculate that day, despite the huge crowd, and the surrounding aroma of evergreen trees between the seven villages of "Old Country" was very pleasant.

The park is laid out as if it were transporting visitors back in time to two picturesque parts of England, Scotland, France, Frontier Canada, Germany and "Oktoberfest," the largest addition to the park and one which attempts to recreate the Bavarian celebration. It has become the most popular attraction. You can also tour the adjacent Anheuser-Busch Brewery.

The most popular attraction at King's Dominion is its Lion Country Safari, which costs an extra $1.50 per person. It began a year earlier than Busch Gardens, in 1974, when you could drive an auto through the game preserve occupied by wild animals. In 1975, the same year Busch Gardens opened, King's Dominion expanded its operation to a full theme park and turned the safari drive into a monorail train trip.

The ride lasts for about 15 minutes while an air-conditioned train snakes through the preserve, passing close by tigers, wildebeests, baby elephants, rhinos, zebras, giraffes, two or three kinds of antelope and ostriches, which seem to play a game of trying to see how close they can stand next to the train without getting hit as it passes.

The King's Dominion theme is not live animals, however. Owned by Hanna-Barbera Productions, it is centered around the company's cartoon characters - led by park employees dressed as Yogi Bear and friends.

King Kobra, a sort of roller coaster that takes passengers upside down through a loop, is expected to become one of the park's big rides.

Spokesmen for the two parks offer this advice to prospective visitors: Sundays are less crowded than Saturdays, except during a Monday-holiday weekend when you should arrive late in the afternoon - never at opening time. In fact, don't arrive exactly at opening time on any weekend. Once you enter and receive a brochure-map, study it and plan your travel through the park. Generally you should go on the rides early in the day or late. Save the midday hours for seeing the indoor shows.

Busch Gardens depends on the 6,000 motel rooms in the Williamsburg area to house overnight visitors. King's Dominion has just opened a 250-bed King's Quarters Motel with rates in the $36 range for a double.

We stayed in Norfolk because the first day of the weekend was spent in the Virginia Beach and Norfolk area. Four hours away, it is a bit far for a weekend traveler, but two more small amusement parks - the better one is at Norfolk's Ocean View, the other at 30th Street in Virginia Beach - are offered along with more than 30 miles of beaches.

We drove down I-95 and picked up I-64 heading southeast out of Richmond, through Hampton Roads and the four-lane, free, Bridge-Tunnell separating the Chesapeake Bay from the mouth of the James River. Take the other route down the Eastern Shore peninsula and you will pay $7.25 in tolls.

We drove the shoreline from southern Virginia Beach to Camp Pendleton Amphibious Base, along the boardwalk commercial area, residential area, through Fort Story at historic Cape Henry, through the Seashore State Park, alongside the Bay beaches and west into Norfolk's Ocean View area. The beaches along that drive are consistently narrower than the ones along the hour-closer, 65-mile stretch of Delmarva beaches we visited a few weeks ago.

But the Virginia Beach-Norfolk beaches are just as clean, the sand just as white and the beach surroundings more varied. For instance, in the residential area of Virginia Beach, private homes back right up to the beach from 43d Street in the south to Fort Story at 89th Street in the north. At the end, back yards are separated from the seawall by white picket fences. In the north, more rustic fences lead up to the dunes, which separate the private property from the beach.

Realizing its potential, Virginia Beach is trying to wrest Fort Story from the Defense Department to turn into a park. It is open to auto traffic now and the southernmost 300 yards of beach are open to the public. Seashore State Park next door is open only to campers or those willing to pay 50 cents to park in the picnic grazzds across the highway. We were, and ate a pleasant picnic lunch among evergreen trees surrounded by sandy soil.

Inside Fort Story is Cape Henry, where English settlers first set foot on American soil in April 28, 1607, before moving up the James River to settle Jamestown. There are two lighthouses there, the other being the original which operated from 1791 to 1881.

The biggest drawback at Virginia Beach is its lack of public bathhouse or restroom facilities. There is only one, at 17th Street, and motel owners complain about people using their restrooms. The one facility was made possible by a land donation from Seascape Motel. The city wants six facilities in all, but can't get the land from other motels along the commercial strip. And the 5,000 hotel and motel rooms along the beach can't begin to fill the demand for accommodations in the booming area.

Property owners in the residential area have successfully resisted efforts to install facilities along the beaches there. The Civic Center Dome, one block from the beach at 19th Street, offers the only other public restroom facilities.

But promoters of the area boast that there is no stoplight between Washington, D.C., and the beach; explain that there is a wider variety of things to do than at the Delmarva beaches, and claim their beaches are cleaner.

Norfolk, adjacent to Virginia Beach on the west, offers historic home tours, historic monuments, the Chrysler Museum, Norfolk Naval Station tours and the Norfolk Gardens.

The Pine Tree Inn in Virginia Beach has been serving meals for 50 years and hasn't suffered from age. It has a pleasant, subtle colonial inn motif and served some of the best, low-priced lobster we have eaten in a long time.

We each had an $3, one-pound lobster (it came from Maine, the waiter had to admit) and ate it by the light of a hurricane lamp in a large, antique-furnished dining room with widely spaced tables.We ate hot, delicious rum buns, then dipped our lobster in drawn butter heated in our individual warmers. We washed it down with a 34-ounce carafe of white house wine, Inglenook, a restaurant bargain at $3.95. We each had a Brandy Alexander parfait for desert, one an Irish coffee and the other a Vandermint Dutch coffee. With cocktails to start, the bill and tip came to $37.93. Entrees range from $6 to $10, but on some seafood the menu notes the "price varies with the tide."

Upcoming events at Virginia Beach include a music festival June 20-23, boardwalk art show June 23-27, antique show July 28-31 and the city's biggest happening of the year, its 10-day Neptune Festival in late September and early October. Despite the special events, surveys show that more than half the Virginia Beach tourists visit Busch Gardens and Williamsburg on the same trip.

For information about Busch Gardens, call (804) 220-2896, or write care of Williamsburg, Va. 23185. The Williamsburg Hotel and Motel Association, toll free at (800) 446-9244, can supply information about accommodations. King's Dominion is reachable at a toll-free number (800) 552-9912 from Virginia or (804) 876-3371 from outside Virginia. Or write them at Doswell, Va. 23047. The King's Quarters Motel toll-free number is (800) 528-11134. Virginia Beach information can be obtained from the Chamber of Commerce, toll-free at (800) 446-8038. Norfolk information is (804) 441-2161.