OP,
It's great that you want to help, my concerns:
1. Apparently the rig is parked at a steep angle based on your gen question. As soon as you get behind the wheel the brakes must be fully functional but the rig has been sitting for an extended period of time. Who knows their condition?
2. The rig breaks down while you're driving - who resolves the issues?
3. Insurance is a big concern. You're driving - who's insurance is in effect? If his and a claim exceeds the limits then what? Or if it's your insurance?
