-- Check out http://www.bikementor.org/
You have to register, but they offer to suggest routes and can give more advice and even a ridealong if you're new at commuting, or would just like them to.
-- I've left my bike outside uptown during the day. I'd probably avoid doing it regularly and never do so at night or durig a football game. Meaning my main worry would be drunks and not thieves. Saw a bike at Johnson and Wales recently that had its seat stolen. I'm not sure I'd park there all day, every day, but you'll soon have a pretty good idea about the area.
-- I live South of uptown and work on South Tryon. I'm not sure if you live south or north of Tryon in U City, but I'm going to throw out a route. It might be worse that N. Tryon, but here goes:
From Trade & 6th, take 6th St. Go left on Smith. Right on 10th. Left on Graham. After Sugar Creek, road veers right and becomes Mineral Springs. And then I'm not sure if Neal Rd. or City Blvd. or IBM Dr. can get you where you need to go. I'm suggesting Graham just because it seems to be a little better than Tryon in uptown. I'm not sure how it holds up as it goes along.
-- For Huntersville, I guess I'd look at Statesville Road (U.S. 21?) and Old Statesville Road (N.C. 115?) first to see if I was comfortable with the traffic there.
Sorry I can't give you more firsthand info on the routes.