Crowders Mountain is a short drive from Charlotte. It is an ancient, magical mountain, with table rock and climbing castles, the colors of the lichens on the rocks are seen nowhere else. One of my favorite walks is up Rocky Top...the views are beautiful the whole way, and it's a good quick cardio workout. Just be sure to leave before dark if you're not camping. The rangers get crabby if you make them late for their dinners.
Pros: proximity 2 Charlotte, beautiful scenery, good workout
Cons: bring water, allow time for return, crabby rangers