@ash78 Tucson is great, if a little niche. My former roommate who went to college here with me is in town for the weekend and she's falling in love with the place all over again, but I'm not sure if it's as much of a destination as the others you mentioned.
There are great natural attractions in the area, like Kartchner Caverns (excellent local limestone cave) or Saguaro national park (notable for the Saguaro cactus, but otherwise not as geologically exciting as Southern Utah). Mt Lemmon rises about 6500 ft above Tucson and the hour drive to the top will take you from cactus desert right into Sierra Nevada-style forested wilderness (and cooler temperatures). Of course the mountains mean there are wonderful canyon hikes as well (Sabino, Ventana) which can get to be quite long and strenuous—my dad loves those.
The border is only about 60 miles away and the drive takes you on the I-19, America's only metric interstate. Nogales is an adorable little border town and there are two cool reservoir lakes (Patagonia and Peña Blanca) that have microecosystems that feel like you're in a different state entirely. About two hours Southeast is the old mining town of Bisbee which has a cute Euro-esque boutique feel.
In terms of history and cool vehicular stuff there's the Titan ICBM silo which I believe may be the only preserved one in the country. There's also Pima Air and Space which has some nice planes (Convair Peacemaker and a Super Guppy are my faves). There's also commercial airplane boneyards up in Pinal that may be tourable, though it's cool to just drive by as well. There used to be the 'Historic Military' Boneyard down at Davis Monthan but I believe it's now closed to public visitation.
The downtown area is real cute and there's been major effort put into making it feel more special, including adding a streetcar to the University campus. Mission San Xavier del Bac is a few miles south and it's quite a notable example of historic architecture (feels better preserved than a lot of California Missions). I think there are some interesting museums downtown as well, like the geology one in the old courthouse.
For kids Reid Park Zoo is a pretty decent small zoo, and the Arizona-Sonora Desert Museum is probably the best representation of the local flora and fauna at any institution. I've heard of 'Old Tucson' as a tourist attraction but I'm a little scared of it. Up 40 miles north in Picacho is 'Rooster Cogburn's Ostrich Ranch' which definitely treats their animals a little more like livestock but seems relatively well-kept. I hear there's a vintage car museum around here somewhere, and there's a museum of miniatures if your kids are anything like I was as a kid.
So yeah on the whole Tucson is a much more 'stay and feel the vibe' kind of place. My family visited and we liked it so much I ended up applying to the U of A and attending, but it can be hard to get past the 'LA but dryer' feel at first. Over time Tucson really shows itself as a true desert city with a heart of gold.