Gas in Toy Hauler Tank

I made my trailer with a 20 gallon gasoline tank and an automotive high output electric fuel pump. I have a steel tank and I try to use up the fuel when I'm not going to use the unit for a few months. In the desert of Arizona we don't have a condensation problem so I don't mind leaving the tank empty for a while. I transfer the gas in my RV, to my Jeep and refill the RV with fresh fuel before I take it out again.
In Aircraft you should always keep them full because of condensation and in the RV I definitely would keep it full if I wasn't in a very dry climate.