For general information on Arizona call 800-842-8257. Country Walkers (800-464-9255) schedules several weeks on the Sonoran Desert in spring, to catch the best of the bloom, and in November, when a wide variety of birds make their winter migration. It offers other walks in settings from Cape Breton Island to Costa Rica and Burgundy. To minimize surprises, you should ask lots of questions when planning your trip and know that within reason you can modify hikes to suit your requirements. Other walking-tour groups include Progressive Travels (800-245-2229) and The Earth Is Yours (708-869-5745).