The wife and I are currently having a home built in central CO. Meanwhile, I received a book last year that I considered to be a 'must have' for any four wheeler (Linked below). Once we're settled into our new location, I expect to hit some highlighted trails from this book.
I can recommend, for now, an easy trail out of Cripple Creek to Canon City named Shelf Road, Phantom Canyon. Really not much in a way of a 'challenge', but the drive was 'dropped dead gorgeous' for this ole' desert rat.