There isn't any truly bullet proof method of maintaining batteries while the coach is parked IMO. If you disconnect batteries then they don't get any charge by definition, and you may find you still have parasitic drains. If you charge them, you need a
really good 3 stage charger that will float them so as not to lose water, and I don't know of any charger that comes built in to a coach that qualifies (I've got a Xantrex RS2000 and I can hear the batteries off gassing while in float charge mode, and I need to add water every 3-5 weeks). The
BatteryMINDer 12248 charging truly disconnected batteries would be a pretty good stab at worry free battery storage IMO.