Err, a Fleetwood of that era would charge the house batts when you're either driving (alternator), parked with the generator running, or parked and on shore power.
If you measure the voltage ACROSS the batteries (you should have installed 2x 6 volt deep cycle batteries), ignoring any wall mounted displays, it should read ~13.8 volts with any of those 3 conditions. That's how it is supposed to work with the installed CONVERTER device which is just a 120 Vac to DC battery charger with some intelligence. The alternator takes a different route of course.
So, measure that voltage across the house and across the chassis batts and let us know. Note that many RVs of that era did NOT install a chassis (starting) battery charging system for when the RV is just sitting in your driveway. So they'd die within 3-5 days because of all the phantom loads. A brand new fully charged batt? Probably dead in 10 days. In those cases we would add an aux charging system for them ~2.5 amp float device from a big box store. Small box, plugs into 120 Vac, wired up to the chassis batts, keeps them charged.
Now, finally, if you plan on storing the RV without power or trying to depend on the mini-solar panel on the roof, note that those are just a rip-off marketing scheme and don't do diddly. Needs to be 100 watt or more.
Until you get things sorted, if it'll be sitting, just disconnect the batt ground leads (after they are fully charged), and remove the jumper between the 6 volt house batts, they'll last just fine for months and months. I always keep a wrench and a pair of gloves in the batt compartment just to be able to do that quickly.