If the weight sheet lists the coach GVWR , ( Gross Vehicle Weight Rating and the GCWR, ( Gross Combined Weight Rating ) The difference between the two will be your tow weight rating.
If you storing the coach inside , do you have access to a plug in ?
Check to make sure the coach charges all batteries when plugged in.
If so you could plug the coach into even a 15 amp; provided the convertor is the only power draw; circuit and the onboard charger will keep the batteries up, you could even put a timer on and only have the coach powered up every 3rd or 4th day. If no power available then removing batteries would be best; and I've never used a special charger for a deep cycle battery, but mine is a progressive 10/5/2 amp charger not a trickle.