Here are a couple pics of our new Whale Seaward S1100.
The front looks similar to (I'd imagine) what your coach originally had installed. The back is pretty plain, but has the two inlet/outlet barbs on it.
The box itself measures 16" high by 16" wide and 22" deep... just about the same size as our original water heater.
This one runs on 110v, and also heats from the engine's radiator when you're running down the road. This one has an aluminum box and an aluminum inner tank.
One thing just came to mind, though... If you're gonna be full-timing and not travelling from one place to another regularly, and are going to be hooked to Shore Power most of the time, you might consider a regular house-type 10 or 12 gallon water heater if you have the room for it. (You know- they look like the steel barrel thing that you have in the basement, but they're much smaller) Probably about a hundred dollars less expensive than a marine or RV style heater...20170315_113224.jpg20170315_113241.jpg
Just another 2 cents!