+1 on wheels....it makes a noticeable difference in ride quality and is safer (though in Tuscon perhaps wet weather safety is not such a big deal).

I have a late 60's/early 70's low end Peugeot and that was the first thing I changed back in the day - steel to alloy. Still have the bike today though its now on its 3rd set of rims (not wear - just fashion).

If it were me I'd also put on a front derailleur - partly because I like things to work as designed and partly because even a casual rider might want the choice of slow tooling around vs. going faster and the investment of $10-20 would give you that option.

Mark