The ideal vision of summer stock: In a quaint mountain town or near a body of water, lots of summer folk gather. The theater is a barn or school. Outside on the lawn kids are painting flats, and everything is done on a shoestring.

Well, things are changing. The towns are still quaint and the kids are still painting, but they have probably paid quite a bit for the privilege. And budgets for some of the big-time summer stock theaters are running in the hundreds of thousands of dollars.

"Summer theaters are becoming regional theaters," says Ted Walch of the Kenyon Festival Theater.

Walch, who 10 years ago ran the St. Albans Repertory Theater and Shakespeare & Co. here in Washington, is artistic director of one of several summer theaters moving beyond the traditional scope of stock to a larger artistic and business vision.

There are two main changes from the past, says Walch: money and talent. Walch's budget is $600,000 for a three-play season. His company this summer featured such luminaries as Joanne Woodward, Treat Williams, Jane Curtin and playwright Michael Cristofer. Walch says, "Now you can attract top talent. They can take risks they can't take elsewhere." He points to Jane Curtin in "Candida" and says, "It's a big risk for her to do the play. She hasn't been on a stage since 'Saturday Night Live.' "

Still, he is disdainful of the word "stock." "We are all of a certain caliber," he says.

Item: The Kenyon Theater Festival production of "Candida," starring Joanne Woodward and Jane Curtin, begins previews in New York Sept. 14 at the uptown Circle in the Square. The production has already been taped for cable TV use.

Item: the American Shakespeare Theatre of Stratford, Conn., production of "Othello" with James Earl Jones and Christopher Plummer, will tour the country for 20 weeks, including a run at the Warner in September, before a planned run on Broadway sometime in January.

Item: The Williamstown Theatre Festival in Williamstown, Mass., is having two productions taped for cable TV. Its production of "A Day in the Death of Joe Egg," starring Richard Dreyfuss and Stockard Channing, is expected to move at least as far south as New Haven's Long Wharf Theater and possibly make it to Manhattan.

If there is a paradigm of the new kind of summer theater, it is the Williamstown Theatre Festival. The setting is idyllic, the performances enthusiastic and the crowds are pouring in. Now in its 27th season, the festival has become an epicenter of the American theater. Much young talent started there: actors like Frank Langella, Christopher Reeve and Jill Clayburgh and directors such as Austin Pendleton, Arvin Brown and David Chambers have gone on to become major forces in the performing arts. They, in turn, have attracted their peers to this festival. This season alone, the stage will see the likes of Richard Dreyfuss, Richard Chamberlain, Christopher Reeve, Blythe Danner, Edward Herrmann, Stockard Channing, Celeste Holm and Dick Cavett.

Williamstown is a highly concentrated celebration of acting. With a budget of $570,000, a staff of 250, including actors, technicians and apprentices, put on 180 performances in 10 weeks. There are full productions in two companies, a cabaret and Sunday special events.

But these statistics don't begin to explain the huge amount of human energy that goes into the summer theater; that is one thing that has not changed in the new era. A performer like Christina Pickles has a chance for total absorption in her work. Her weekend might go like this: Friday night, perform in "Summerfolk," a 3 1/2-hour play by Maxim Gorky. After the play there is a company photo call that lasts past midnight. Saturday she rehearses Noel Coward's "Nude With Violin" and runs through "Joe Egg." The Gorky starts at 5, finishes at 8:30 and starts all over again at 9:15. Sunday is rehearsal and a performance in the special events series at the Clark Art Institute.

Nikos Psacharopoulos, one of the founders of the theater and its artistic director since 1956, says, "It pushes it a bit; sometimes we aren't ready. But I think a Picasso that is done in five minutes is more interesting than a Dali done in one year."

For Psacharopoulos, rehearsal is a time to "find out what's wrong rather than what's right."

A rehearsal on a recent gray summer afternoon went like this:

Richard Dreyfuss is sprawled on a scruffy rehearsal couch, his face puffed out. He looks like a gray-haired kid with a permanent case of hay fever. He has pinkeye, and he is waiting for drops to come from the doctor.

It is Saturday afternoon and he and Stockard Channing are about to find out what is wrong and what is right. They are starring in a revival of "A Day in the Death of Joe Egg" by the British playwright Peter Nichols. After only 10 days of work their first run-through without book is about to take place in a rehearsal room under the main stage.

The room is black from floor to ceiling. Strips of tape on the floor outline the actual playing area. Not all the props are ready to be used. Watching this run-through will be like reading an X-ray.

There are about a dozen people watching. As is customary, the artistic director sits in. There are several directorial assistants and a few friends of the theatrical family.

No Lights, no curtain. "We will begin when Richard's ready," says the stage manager, Scott LaFeber, who readies his stopwatch to time the act. "Joe Egg" tells the story of Brian (Richard Dreyfuss) and Sheila (Stockard Channing) and how they cope with their 12-year old daughter, Josephine, who is a spastic, epileptic "vegetable." The play is a comedy. You hurt till you laugh.

The play begins with Dreyfuss, whose character is a secondary-school teacher, trying to keep discipline in his imaginary class. The audience becomes the class. He works the monologue like a veteran comic. Building his jokes, making eye contact with individuals, drawing the laughs.

As the act progresses, the performances' energy varies. Some bits, the times when Sheila and Brian are relating to each other without a lot of stage business, work very well, and are ready for any audience. Other moments -- a music hall routine about the ignorant doctors who caused Joe's illness, for instance, are pushed and manic.

Then an amazing moment happens:

Dreyfuss is kneeling on the couch confronting Channing with her infidelity. The actor is crouched over Channing, the pain of jealousy wrapped in a self-mocking accusation, his speech fast. Channing looks up at him paralyzed with guilt, even though she is innocent of his accusations.

Her eyes are glued on him, the energy is high, the pace is right, the audience is leaning forward rapt and -- PAUSE -- Dreyfuss says, "Line."

His eyes don't waver, the mood doesn't change. The communication of inner pain is so strong that it takes those around him a moment to realize that the actor has dried up on his line.

The moment is extraordinary because it shows so clearly the process of building toward a performance: The activity the actor is involved in or the attitude he is physically communicating often tells the audience more than the words he speaks.

The stage manager reads Dreyfuss the the line, and the scene continues.

When the act is over, Dreyfuss rushes for his eye medication. The other three members of the cast arrive. John Tillinger plays a do-gooder friend of Brian's and Christina Pickles is his less-than-enthusiastic wife. Kate Wilkinson plays Dreyfuss' mother. The second act is rougher. There is more intricate stage business and the act suffers more from the artificial atmosphere of the rehearsal room. Arvin Brown, the director, is crouched by a piano in the corner silently mouthing each line, scribbling notes. The play winds down to its end. The framework of a good show is truly in place.

While everyone was in the black room, the sun broke through. Dreyfuss and Channing take a slow walk toward the main street in search of a sandwich. But every place is crowded and there is a film crew from some cable outfit prowling around, so they decide to go get a car and drive outside town.

As they go back up the hill, it's observed that two weeks isn't really enough time to work on a part that requires an actor to be on stage for two very physical hours. Channing, drained from the rehearsal, agrees. "There's a limit to how much you can absorb in two weeks. Yes, I feel pressure."

Just then, one of the director's interns wanders by. "What'd you think?" asks Dreyfuss. "Real good," the intern smiles back. Channing gives Dreyfuss a shove, "People always say that. Geez, what'd you expect him to say?" Dreyfuss laughs and shrugs. Everyone laughs. Has anyone in that situation ever told him he was bad?

"Yeah," he says, scrunching his face up at the memory. "Once I was outside a theater where a film I was in was playing. I was looking at the marquee, and this guy came out of the theater. So I asked him, 'Did you just see the movie?' He says yeah. 'Did you like it?'

"No, not really."