Thanks for the advice. From what I've been able to dig up, the bike was some attempt by Mongoose to get into the cross market.
i normally ride 700x23 but I can fit up to 32 on my frame so I went with some "city" tires that aren't real knobby but have a bit more tread than my road tires.
i hadn't looked for fenders or rain gear yet but I'll look into those.
Mirrors didn't even occur to me so thanks for bringing that up.
I'm assuming I'll figure out what works for me as I go, but these seem like good places to start.