One suggestion I always make to people considering spending any significant time off grid or upgrading electrical systems in RVs or Boats is to first invest in an energy monitor.
They are cheap and IMO one of the best gauges that you can have.
They are like a fuel gauge for your battery bank and are indispensable in helping you size your electrical system should you decide to go with a real boondock setup.
Even if not upgrading - they let you know and understand the state of your batteries at any given moment.
They tell you what you've pulled out - put back in - what you are pulling at any given moment. They really allow you to easily monitor and manage your power.
For the RV - The Trimetric is a good unit. Easy to install.
Link to info on it is
HERE.