It’s gonna be hot, so to make it enjoyable, be mindful of how much stuff outside
That said, Pima Air Museum is pretty cool. Quite a bit is outside though
There is an underground mine tour in Bisbee
Kartchner Caverns near Benson is really neat but you will have to check if tickets are available as that’s how they limit access so as to not damage the ecosystem as the cavern is still forming. There is Colossal Cave, a dead cavern so unlimited access, is on the east side of Tucson.
Tombstone is touristy but you might enjoy it
Just for a drive, you can drive to the top of Mount Lemon. You start at about 2500 feet at the bottom and to like 9000 feet at the top. A twisty, windy paved road.
There is a State museum there in Tucson
San Xavier del Bac is an old Spanish mission built about 300 years ago. Not really far from downtown.
This is a good list. I'd add the Asarco Copper mine tour and the Titan Missile Museum as additional options, depending on your interests. Not too long ago I'd have added heading down to Nogales, Mexico, but those days are over.
