I described the actual process in reply to another comment a few messages down. You can dump the waste and fill up with fresh water at a lot of different place

I described the actual process in reply to another comment a few messages down. You can dump the waste and fill up with fresh water at a lot of different places. Most Flying J truck stops have an RV dump and potable water supply, as do many highway rest stops and state parks. Some RV dealers have facilities, too. And there's always RV parks like KOA, but you generally have to pay a small fee to dump and get water here if you're not staying the night. Also, the RV community is friendly and connected online. Some folks have installed dump stations at their homes for their own RVs and will let you use that in a pinch if you ask nicely.