There's no reason to cycle your batteries every month. It might be good to equalize them from time to time but the motion of an RV typically keeps the electrolyte stirred up. Equalizing isn't as big a deal with an RV as it is with a home or cabin battery bank that just sits there in the basement.
Keep in mind that you MUST have batteries installed in your trailer to legally pull it down the road. They power the brakes in the event of a breakaway. If you have no batteries your disconnected trailer has no brakes and becomes a dangerous missile.
If you have a good solar charge controller that is properly set up for your batteries there's no need to ever unhook it.
