Your salesman switch (use/store switch or master power switch) disconnects the house batteries from NEARLY everything electrical in the coach including the coach's charger and the coach's alternator. IThe switch is there to remove the power to an inventively light left on in a lower compartment, the slide's controller using power to lock the slides in position, etc. Some coaches may be misfired.
The chassis battery has considerable battery drain for both radios to keep the memory alive. Same for the engine's and the transmission's computers memory. Disconnecting the chassis battery for more than 20 to 30 minutes will automatically erase all "learned things" in the computers and return the radios and ECU's to their original factory programing. To keep all batteries chaged, you must have 120 volt power to the coach, or individual powered chargers in the coach or remove the batteries and store then on a dry, heated enclosure and use a trickle charger if the coach is to be in long term storage. It is not a car. What works with your car is usually not applicaple to a motor coach. You a supposed to run the generator for an hour under load every 30 days to remove mosture fron the stator and rotor in the generator. Even that should keep the batteries reasonaly well charged.
