A cat peeing in an author's bag? A writer waking up to discover that a complete stranger has left him four jars of delicious homemade preserves? Such things are not traditionally part of book promotion. But they happened to Bill Cotter and Annie La Ganga, an Austin, Texas-based couple who celebrated the simultaneous release of their debut books this fall by jumping in their car for an 8,500-mile, 27-day, do-it-yourself tour.