Welcome to BF. I graduated from the U of A in 83, but haven't been back to visit since about 87. I imagine Tucson is quite a bit larger now. I started riding again about a year and a half ago having not ridden at all since the 70s (I rode a Yamaha 500 when I lived in Tucson). I wasn't more than a few pound overweight when I started riding, but promptly dropped 15 to 20 pounds and have kept it off. Wasn't why I started riding, but I'm not complaining about that outcome.

I mostly ride alone and usually do about 35 miles, but when I have time I do 50. No reason to fear riding alone. Carry a spare tube and tire tools just in case. Otherwise, there isn't much that can go wrong if your bike is in decent shape. And if it's at all warm out, bring two water bottles. One won't cut in hot weather and doing the last 15 miles without water can be tough.