Tucson Mountain Park and the Arizona-Sonora Desert Museum first thing in the morning. The museum is a world-renowned zoo, natural history museum and botanical garden, all in one place. Lots of outdoor walking.
Gilbert Ray campground near the museum has first come first serve camp spots. The mostly outdoor museum was so vast, I was able to return 3 times that day with siestas at my nearby campsite in between visits. With temperatures in the 90’s, mid day activity is limiting. Lucky Lulu has air conditioning.