Get that gigantic backpack and sleeping bag and trek on over to Cody's Books on Fourth Street, as Tony and Maureen Wheeler, the founders of Lonely Planet, read from their new books, Unlikely Destinations (the story of Lonely Planet) and Bad Lands (Tony's trips to dangerous countries). If you can't make tonight's reading (7 p.m.), they're in town through Friday, reading at Get Lost in SF tomorrow night and Book Passage in Corte Madera on......