We're thinking of taking a side trip from LV (as we almost always do), this time to southern AZ to see Saguaro NP, Karchner Caverns, Chiricahua NM, Tombstone and whatever else strikes our fancy. We have 4-5 days to do this. I'm having trouble planning an itinerary without doing too much driving in one day. We'll probably stay at Harrah's Ak-Chin on our way back but don't know about the rest of the trip. Is the Biosphere worth a visit? Sonoran Desert Museum? HELP, please!