Chassis draining has been covered and the knife switch (or similar) is always a good idea. In addition, most coaches' steps are powered by the chassis. Some have reported the steps being a large drain on chassis during storage. Others have even reported the step light remains on whenever the steps were out. Anyway, something to investigate if you get curious.
As far as the BDS, some coaches do not cut power to the safety systems (C02, propane and smoke detectors) and many have come back in a month to find dead coach batteries because of this. Something else to investgate if you wish.
John & Clare - Buck & Zeus - Jack & Husky
2008 Fleetwood Bounder 38P
Towd: 2 HD Streetglides