multiple problems with new Forest River

Sounds like the fresh water tank and heater issues have been answered. Regarding the battery, I'd recommend you head over to the "tech issues" sub forum. You could spend all day (or all month) reading about batteries and charging. Bottom line, the single 12V group 24 battery you likely have is not really suitable for dry camping. If you want to dry camp, you need to upgrade the battery. Also, you mentioned running the generator for 6 hours! With a proper charger, you should be able to cut that to an hour or 2 at most. May want to consider solar too. Fact is, most RVs from the factory are set up to be "pedestal queens." Successful dry camping will require upgrades.