You don't need BackToMyMac to do that kind of stuff.
Set up a admin user with a secure password, get a IP forwarding service (like dyndns.org) and install a client that updates the database with your computer's IP, and, for good measure, install the LogMeIn client (just in case the computer sits behind a router when used). If you're paranoid, you could HamachiX to it, just as a safety net.
Voila, you should be able to get access at any time.
-t