The first thing to be said about the Bohemian Club is that no bohemians would be allowed in -- and haven't been since it was founded by some boozy San Francisco newspapermen around the turn of the century. What distinguishes this club from others just as prestigious, though, is the Grove, the summer encampment held every July on 3000 isolated acres of redwood forest north of the Bay Area for which the great and powerful from around the world interrupt their affairs, if only for a weekend. A chance to be boys together. Because there's a code that nobody writes about what goes on (what self-respecting muckraker would trouble about such nonsense?); van der Zee, even with credentials that could have gotten him invited as a guest, decided to get in through the kitchen door. So it's the hired help here, most of them homosexual, who have the pizzazz. For the rest. . . one longs for a hint of gossip to lift the tedium; a corporation executive (not even a cabinet member) hanky-pankying with the ""girls"" up river or the scullery crew. What we're given instead are anecdotes about Hoover -- yes, that one -- and what Nelson Rockefeller wore one year when he came to test the political temperature. (We might even have been contented with an anthropological study of the male bonding rites among the Establishment.) If the Bohemians are apprehensive about this first-ever expose of their encampment, not to worry. Van der Zee never got dose enough to get a splinter and he's been altogether respectful of the old froggies.