Arizona made me think of one for you. How about hiking? Down the Grand Canyon, stay a night or two at the bottom, then back up again. It shouldn't be too hot at the top, but will be at the bottom. The Canyon is beautiful though, if you've never been I would definately put it on your list to check out. I was there in May and stayed one night (at the top). We mostly walked around the rim, but I would love to go back and hike down and up it, assuming I could get myself in good enough shape.