THE VIEW GETS bluer and the road gets narrower the farther you drive into the Virginia countryside. Red wing blackbirds adorn the telephone wires and spring seems more vibrant out here where there are fewer people and more horses and cows. On the newly green landscape the historic houses of the Old Dominion stand tall and dignified, inviting a visit, and there's no better time than May to take a country weekend and pay them a call. Top it off with a stay at a rural inn.

The Civil War, in its sweep through the south, worked cruel hardship on these beautiful mansions, and the owners usually had to sell the furniture and pieces of the land to survive. The 20th-century enemy is inflation, and its effect is almost as threatening. Maintenance, wages, utilities and the price of the tourists' gas bite deep into the solvency of the Virginia great houses.

Morven Park in Leesburg is opening a month late this year. Belle Grove in Middletown is on an economy heat and light regimen, the gardens at Oatlands in Leesburg have been neglected for lack of funds. And always the developers hover on the edge of the land, waiting to move in. The budgets for the great houses are feeling the pinch. Who knows how long the nonprofit organizations administering these houses can keep the bulldozers at bay?

The time to go is now and Oatlands is a good place to begin.

Oatlands is an anomaly, an 1800s house with 1900s furnishings. It was built by George Carter about 1800 on what was originally 5,000 acres, a present from his father on his 21st birthday. He lived there for most of his life in solitary splendor. Not until he was 60, and a widow who had had a carriage accident came knocking at the door, did he succumb to marriage.

Nine years later he was dead and after his wife returned to her girlhood home, Oatlands became a billet for Confederate troops. At the close of the war, one of Carter's sons came here with his wife to live, bringing with him his widowed mother, but money was such a problem that eventually all furniture except the massive sideboard in the dining room was sold. The current beautiful furnishings are those brought to the house by William Corcoran Eustis, grandson of the founder of the Corcoran Gallery and Riggs National Bank, who journeyed out from Washington with his wife on day in 1903 and bought the property without even seeing the inside. After their deaths, Oatlands was given by their daughters to the National Trust.

Eustis was a man, whose life revolved around horses; Oatlands, deep in the heart of horse country, reflects his love. Every April it hosts the point-to-point of Loudoun County on a permanent course of 24 fences, and in May it welcomes the Loudoun Horse Show. Eustis' hunting pinks are forever laid out ready on the bed and hoofs from his favorite mounts have been fashioned into an inkwell and a stamp box.

Elegance is the hallmark is this house, which is always full of flowers. The knife boxes on the Carter sideboard hold silver service for 20, the dessert plates on the dining room table were purchased from the heirs of George Washington. Among the portraits and drawings which hang by wires from the moldings in the turn-of-the-century manner are four Piranese engravings. The octagon sitting room, a special favorite of Edith Eustis, is a jewel.

High winds recently caused the chandelier in the hall to fall from its medallion, but elsewhere the intricate plaster moldings of Oatlands are intact. The Corinthian capitals of the front columns are at eye level from an upstairs window and worth a close look. They came by ship from New York to Alexandria and from there by ox cart. The sparrows are nesting happily in their leaves.

The formal gardens, inspired by the Italian models but typically Virginian, were restored by Edith Eustis and are said to be among Virginia's finest. Primarily green gardens, they feature English boxwood, which grows so slowly that some of the larger ones have reached a size that might bring $10,000. Down by the sundial, if you look carefully, you will see the footprint of a dinosaur on one of the paving stones. You can also chat with a llama, who bats his eyes across the fence at visitors. Watch out -- he spits.

Belle Grove, a mile south of Middletown on Rte. 11, is quite another sort of great house. A working farm, it was the 18th-century home of Issac Hite, one of the German farmers who settled in the Shenandoah Valley, then sheltering a large German community.

Belle Grove is the only Jefferson-designed stone house in America. In 1783, Hite married Eleanor Madison, sister of the future president, who interested Thomas Jefferson in the plans for the house. It is errie to stand in the hallway two centuries later and see fanlight over the door that Jefferson is thought to have designed. The tightly-curled staircase leading to the attic is Jefferson's also, and you must climb it, however difficult, to see in the attic the names of Union soldiers written in candle smoke on the ceiling.

Here in the Shenandoah Valley some of the bloodiest battles of the Civil War were fought, and Belle Grove was the scene of one on the most famous, in 1964, when Gen. Philip Sheridan made his headquarters here. In the early morning hours Confederate Gen. Jubal Early surprised the sleeping Union army drawn up around the house, triggering Sheridan's famous ride from Winchester to rally his troops. From the mountain top across the way, Union soldiers often signaled headquarters by torchlight, passing news of troop movements to watchers on Belle Grove's roof. (It is a miracle that the old house never caught fire, for when each exchange was over, Sheridan's men simply tossed the flaming torches over the side into the garden.)

Various families have lived in Belle Grove since Isaac Hite. The last owner was Francis Hunnewell, a man who understood the place of his home in history and willed it with 100 acres of farmland to the National Trust. To this day it continues as a working farm, linking the centuries it has seen with the crops that grew both then and now. The present farmer, born in Belle Grove's dining room, was given the right to farm here for his lifetime

The scale of Belle Grove is overpowering. Ceilings tower far above your head; the lock on the front door must weigh several pounds. The doors are all on drop hinges so that they close silently behind you. Hite married twice and fathered 10 children, and it could be that this accounts for the fact that he liked a shut door.

Sarah Hite's wedding dress, so simple it looks like a christening gown, is on display, and Edwin Watson, director of the nonprofit Belle Grove, Inc. which administers the house, is thinking nervously these days about washing nearly two centuries of dust from it. Patrick Henry signed Major Hite's commission, which appears in one of the display cabinets. It seems incredible to find these things still here.

Naturally such a house would have a ghost. Hattie Cooley, mistress of Belle Grove in 1861 who is said to have been murdered by her slave, Harriet, occasionally walks the premises. She was last reported seen by a workman who said he was confounded to watch her apparently walk straight through a wall and ascend. It seems she was only using the stairs which had been there in her time.

Currently a collection of early textiles from Frederick County hang on the walls of Belle Grove. (Number 31 is perhaps the finest quilt ever to come to the state of Virginia, says Watson.) When that display is gone, sometime this month, a needlework exhibit is planned. The current trend is to use the great houses for public events in keeping with their atmosphere, such as classical music concerts, crafts exhibits, folk art festivals.

Morven Park will be hosting June 14-15 a horse and rider competition that requires contestants to complete 100 miles in 24 hours. Ed Maurer, director of the mansion, is also anxious to bring poetry readings and chamber music to the property.

Morven Park was originally the home of Thomas Swann, an early Maryland governor. It usually has 16 rooms open to the public, and its carriage museum with more than 100 horsedrawn vehicles is rather famous.

When it's time for a bit of rest and refreshment, what could be a better choice than the Wayside Inn in Middletown, in business since 1797? In those days the inn used to send a servent boy up the hill to watch for a cloud of dust on the horizon that might mean travelers approaching in need of hot food. The Wayside is furnished with antiques; its floors complain and slope noticeably; it has no room telephones or television, and is, all in all, a splendid change from the motels. Wings have been added since the day when Stonewall Jackson's famous Valley Campaign swept past a few miles away, but there are still only 21 rooms.

Forty dollars here could but you a pleasant sunny suite for two with antique furniture including a four-poster, possibly canopied, and beautiful random-width floors unmarred by carpets. You'll carry your own bags up the stairs and you can't ring for room service, but enroute up you can see a piece of wood authenticated by notary public as part of the cherry tree chopped down by George Washington. An ancient volume on the Civil War lies open on the table in the sitting room, and a telegram from John D. Rockerfeller Jr. requesting rooms is framed at the foot of the stairs.

I forgot to bring any reading matter for my stay, but it didn't matter. I had a choice of books in my room, including "Moby Dick," a novel by Harold Bell Wright, and "Volumes of Useful Information." If you are not in a reading mood, you could sit a spell on the rockers on the front porch, studying the early motor car chained to a pillar and the traffic going by on Rte. 11. The advertising for the Wayside Inn boasts that it was America's first motor inn, but this shouldn't be held against it for it has been diligent in preserving its stagecoach-era charm.

Meals are served in an attractive dining room by waitresses in Colonial costume. The food is rural southern, with emphasis on spoon bread, ham and fried chicken in batter. It may not win any gastronomic prizes, with its serve-yourself salad bar and its sometimes overcooked vegetables, but the peanut soup gets an A-plus and so does the complete individual loaf of bread brought to every diner to slice himself. Moderate prices.

Two caveats on the Wayside Inn. You have to pay in advance or let them charge the room to one of your credit cards. If you have to change your plans and don't give 48 hours notice, you don't get your money back if the room isn't subsequently rented. The other oddity may not bother you, but it did me. The faucets -- at least in my room -- worked in reverse to the time-honored left-to-loosen, right-to-tighten formula.

In June the Wayside Theater, just down the road, will start its summer season again with performances by professionals. Call 703 -- 869-1776 for information.