I live in Indian Trail which is a suburb east of Charlotte. Charlotte is a fast growing city and the traffic shows it.
Cycling is very big here. I tend to stay away from anything to do with Uptown Charlotte or the metro area. I usually ride the outskirts of Charlotte (Waxhaw, Mint Hill, Locust, Ballantyne, Belmont, etc.) due to having a lot less traffic and plus the country scenery is great. For MTB riding you have the US National White Water Center which is great. Over 30 miles of trails. There are also some other trails near by (COL Francis Beatty park, Sherman Branch) and you have some state parks that have trails as well (Uwharrie State Park, Lake Norman state park) and you can always head up to the mountains where the riding is great and the scenery better. Rock Hill, SC which is about 30 mins from my house has the Rock Hill Criterium Course. Lots of riding around here and overall good place to leave.