I guess that I am one of the lucky ones. My battery disconnect turns off everything in the trailer, Actually that is another reason i was looking into solar. Tjhere are some things that I would like to keep powered if possible. my new propane detector has a led readout that is shut off when the disconnect is on and I have a trailer leveling device that needs to be charged prior to use. I also have a battery monitor and shunt,not sure if that is affected by the disconnect or not. I dont think so but I'm not certain.
I may look into one of the solar maintainers or possibly a 100 watt panel to see how that would work.