A small yellow school bus, carrying Fairfax County school board members, concerned parents and one county supervisor, wound its way along the rainy backroads of the county last weekend.

The passengers were looking for vacant lots, and as the passengers on the bus would tell you those lots could mean the difference between keeping a school -- in this case, Wilton Woods Elementary -- open or closing it.

The point, according to the parents, is that the Lee Supervisory District, where Wilton Woods is located, still has the potential for an increase in the number of school-age children because of housing developments now under way.

Wilton Woods is one of eight county elementary schools that Superintendent L. Linton Deck and the school planning staff have recommended for closing next year because of declining enrollment.

The bus trip was one of several lobbyig efforts launched last weekend by citizens opposed to the superintendent's proposals.

Acting as tour guide for the Wilton Woods group was county Supervisor Joseph Alexander (D-Lee), who argued that much of the information used by the school planning staff on school closings is faulty.

Alexander singled out school population estimates, which predict Wilton Woods and surrounding areas are going to lose students during the next five years. Pointing to the vacant land which abounds in Lee District, Alexander says housing developments now being built mean the school-age population is going to increase.

Alexander was careful to add that many of the builders already have submitted site plans and secured financing and are thus relatively unaffected by the economic problems affecting much of the nation's construction industry.

As the bus rolled along, Alexander unfurled a map of proposed housing developments and correlated the map with the landscape.

"We are going to experience the same type of growth they're seeing over there by the Huntington Metro stop," said Alexander, referring to the real estate boom in neighborhoods near the future subway stop.

As the school board members dodged a sudden downpour and ran for their cars at the end of the tour, anxious Wilton Woods parents surrounded Alexander to ask if he had been successful in convincing board members to spare Wilton Woods.

"I think we planted the germs of some ideas," Alexander told his constituents with satisfaction.

Board members on the tour were Chairman Rodney F. Page, Vice Chairman Ruth Dell, Mary Collier, Robert Frye and Gary Jones.

School board members said later that Alexander had gently applied political pressure as he escorted them around Lee District, but most said the trip had been helpful.

"I think we all recognized that that's what it was (political pressure)," said school board member Collier. "But he had every right to do it, and it was informative to me. I never realized how big Lee District is."

Wilton Woods parents were not the only ones who were organizing after Deck announced his school closings plan last week.

At Masonville School, which also was recommended for closing, parents were fuming over a bond referendum which the community supported in 1975 to renovate Masonville. Parents say they find it ironic that the more than $100,000 approved in the referendum has yet to be spent on the renovations, and now the superintendent has proposed closing Masonville. "We worked hard to get that bond referendum passed," said Karen Womack, a Masonville parent, who recalled being "stunned" by the news that Masonville could be closed. "The only way they (school officials) can get that money for anything but Masonville is to close the school."

Other school communities were preparing letter-writing campaigns and petition drives. Spokesmen from nearly all affected communities said they were investigating legal action if the school board votes on May 22 to close their schools.