Stand-up humor which lies down occasionally in an exhaustion of one-liners, this strenuous pig-sticking of American vacation lures nonetheless has its moments. New York City seems ""to have been founded last Friday by George Orwell and Howard Johnson."" On Grand Canyon atop a seat-paralyzing mule: ""I would wander forever in that crummy grandeur, shrinking from thirst and running up overtime on the mule."" Throughout the tours of Washington, New York, Las Vegas, Disneyland, L.B.J. country, Mr. Schoenstein totes two small daughters; endures wifely comments on his driving; weathers the onslaughts of his fellow Americans, hawking and buying souvenirs (from ""holy water"" from the Pedernales River to T-shirts that sport the word ""Schlitz""); and suffers the slings and arrows of suitcase living. The skies burn and so do ingested hot dogs; the wooded and un-wooded steams rock of pollution. In spite of the lullaby of Disneyland, and the wondrous magnitude of topless San Francisco, it's a rough go. See America last.