Wigs and he is a very good mechanic and has a good stock of bikes. Fun Wheels in Oxford is another really nice shop with lots of stocked items.
It's about 4 miles from the main gate at Weaver to Bains Gap road and 5 miles on Bains Gap but the White Plains side of the pass is even steeper than the Ft. McClellan side. Whenever I go there I take as little as possible even removing the Cyclocomputer from my bike. I've yet to make it over and "pop" when I hit that last increase in grade near the top so I can't give exact mileage.
Ft. McClellan is a nice place to cycle with little traffic and low speed limits. It's a neat place to explore. Here is a map showing all roads and barriers.
http://www.mcclellan-jpa.com/images/...rity_gates.pdf