diesel fuel / unlock the steering column
the best advice on fueling diesel is to go to a station that pumps alot of fuel. This should help present taking on any water. The green pump handle is what you look for. Shell, Exxon, Hess, all the big fuel brands are ok.
RE: the steering column lock. Turn the key to the point where the steering wheel turns. This critical so that the front wheels will follow the coach as it moves forward. DO NOT BACK UP AT ANY TIME, THIS WILL CAUSE THE FRONT WHEELS TO TWIST AND BEND THE TOW BARS(been there, don't want to got there again). Look into an on/off switch for the ignition circuit to present draining the car battery (there are several threads regarding this on this site).
Good luck, enjoy your travels, be safe.