Climbing ratings go from 5.5 to 5.15.
I do climb outside regularly when the weather allows. There is Red River Gorge and New River Gorge within a 4 hour drive and some of the best sport climbing in North America is in these two places. I currently have a 10 day trip planned to start in Chattanooga, TN and work my way North through Tennessee in April.
The climbing gym is a good place to get started in climbing and work on whatever you need to so you can progress outside.
You'll find some muscles groups you don't work out in any sort of gym environment.
I need to start utilizing the weight rooms to help promote muscle growth in some areas. Soon I'll be climbing with a weight vest but I want to let my tendons in my fingers get stronger first so I don't hurt myself before the warm season.