Welcome to the Forums. You will find a lot of helpful people and threads here to sift thru with lots of useful information. There are two water heater manufacturers to chose your W/H from. One is Suburban and the other is Atwood. Atwood is a better "fit" in my opinion. There is also a "tankless" model available from another manufacturer, whose name escapes me at the moment. Take some measurements, and I am sure you will find a good replacement model.
Kev