If camping in cool weather (highs @ 20F and colder) even with a well insulated RV, you will use a lot of propane. As we do a lot of cool weather boondocking , we carry a 50 gallon tank ( was a propane fuel tank for a pickup truck), on our extended winter camping trips. It is a bit difficult to move around ( remove from truck or trailer (if pulling doubles) and position for use. Once positioned, we merely run a hose from the tank, to one of the RV propane connections. You still have your regulator and auto tank swap in service. There are several different shapes and sizes of auxiliary propane tanks available on the internet.
“If” you will be stationary for long periods of time, a larger rental tank would be a great option. You could do the same connection as we do with our portable tank.