Added a breaker to the panel.
Ran the wires under the camper in a conduit over to the water heater compartment. Had to drill through the floor but sealed it up well with spray foam as well as caulk around the outside.
Screwed the outlet down to the floor.
Thermostat attached to the back of the water heater.
Switch installed so the panel can stay closed and plugged in.
All in all it was a pretty easy project. Would have been nicer had an outlet been close and if I could have gotten up the wall with the switch but didn't see any good alternatives to what I did. Thanks for all the help and looking at the finished project.