Another in Delaplane's series of international wanderings, this concentrates on the foreign country to the south of us and, with the most casual of touches, presents a running commentary on all aspects of travel and living there. By bus, car and plane he covers all areas, rounding up what to see and do and eat, what to buy, and how to cope with the telephone, the roads, the language and the maladies that might attack the careless one. He makes sure you understand the manana and ahorita attitude, gives you a chance to decide about bullfighting, tours the ""gilded triangle"" of Mexico City, Cuernavaca, Taxco and Acapulco, and is firm about other sections and stopping places off the main routes. Not the standardized guidebook but one with hidden dividends in its simpatico approach and its odd and personal items of information. A hodgepodge --in high, good humor, familiar to readers of his columns and previous books.