There are times when weekend vacationers from the Washington and Baltimore areas can't travel to and from Maryland's Eastern Shore as quickly and effortlessly as they would like. It has been that way for as long as anyone can remember.

Despite the addition of a second bridge across the Chesapeake Bay, it will be that way for the next five years, at least. It may be that way forever.

Those were the pessimistic - though perhaps unavoidable - conclusions reached here today at a two-hour brainstorming session that featured Acting Gov. Blair H. Lee III, a host of map-toting highway planners, and an aggressive group of officials and businessmen from besieged resort towns on the Eastern Shore.

They were told that several minor projects to clear bottlenecks along the route could cost up to $200 million and will not be ready for construction until 1982, at the earliest.

In the meantime, they were told, the State Highway Administration and Maryland State Police have done about all they can to ease the traffic burden, which sometimes, such as last Memorial Day Weekend, turns a two-hour sprint to Eastern Shore resorts into a seven-hour ordeal.

"I have learned quite a bit since I came into this room," said Lee, after listening to the testimony. "But I can't say that I'm much happier."

Lee called the informal session at the urging of Harry T. Kelley, the fast-talking and eternally optimistic mayor of Ocean City, who told anyone who would listen to him that "I have never lost a battle with the state in my seven years as mayor and I don't plan to lose this one."

Kelley had his own plan to get tourists in and out of his territory more quickly, and he gave it on Lee and the highway officials shortly after he gave the acting governor a gold key to Ocean City. Kelley's plan was simple, although the grimaces on the faces of some bureaucrats in attendance implied that they did not find it all that ingenious.

As Kelley saw it, the traffic jams occur because the vacationing, motorists, who sometimes number more than 40,000 in a day, all travel on basically the same route between Ocean City and the bridge. He said there are actually six or seven alternative routes that could be used. Three of them would require extensive travel along the roads in neighboring Delaware, then down toward Baltimore on Route ?? or Interstate 95, however.

"What we could do is mark out these routes in A,B,C,D,E,F fashion, print them in the newspapers and brochures, and then have the radio stations and signs along the highway tell motorists which ones are free of traffic and so on," said Kelley. "I've tried these routes myself, and none of them take more than three hours."

Kelley said he liked his idea so much that he would have Ocean City "foot the bill" for the newspaper advertisements and brochures. "If we don't (do something like that)," he told Lee, "we're gonna have a monster on our hands."

Lee accepted Kelley's idea without comment, but a state highway official pointed out that "Delaware has become very concerned about us telling anyone to use their roads." Kelley retorted that Delaware had little to complain about, since "so many people with D.C. and Virginia plates use Maryland roads to get to Rehoboth (a resort on the Delaware shore).

State Highway Administrator Bernard Evans outlined the construction projects along ROutes 404 and 50 on the Eastern Shore that could lessen the traffic jams. But he did so with a tone of doubt that the projects will ever be undertaken. "I don't see those funds in sight," he said bluntly.

Even without the funds in sight, however, Evans said "top priority" has been given to three projects. The first would be a bypass for Rte. 404 at Denton, with an estimated price tag of $16 million. Next would be a greatly expanded interchange at the intersection of Routes 404 and 50, costing an estimated $5 to $8 million. And finally, at a cost of at least $38 million, the entire highway from the eastern end of the bay bridge to Queenstown - a 12 mile stretch - would be turned into a six-lane freeway.

Thomas Hicks, an engineer with the State Highway Adminsitration, noted that short-range solutions to the traffic congestion have included everything from sending up state police in helicopters to search out problem areas to installing computer-operated traffic lights along Route 50.