Welcome to iRV2. You have bad batteries or there is a considerable drain on them. If you are looking for possible drain circuits, consider posting this in the Winnebago Owner's forum. From the main page scroll down to the Owners Corner. Inside the Owners Corner there will be a forum specific to Winnebago. They are in alphabetical order so Winnebago will be at the bottom of the list.
I make this suggestion because different manufacturers wire their coaches differently. This drives owners (and technicians) crazy. Being a Newmar coach owner, I could make some general suggestions, but they may be useless to a Winnebago owner. Also consider adding to the content the year, model, etc. of the coach.
2005 Newmar KSDP 3910 + GMC ENVOY XUV 37K lbs Moving Down The Road
The Avatar Is Many Times Around The USA
Nobody Knows Your Coach Like Somebody Who Owns One Just Like Yours