All of the feedback has been very insightful and valuable, I really appreciate it!
I like the idea of living on a mooring at a marina, it seems to fit what my son was proposing. True, the electrical demands of the boat would be greater than if we were "plugged in" at the marina, but I've also dreamed of off-grid / self sustained living.
Today's lack of liveaboard slips and mooring-living options leads me to wonder if it would be difficult to obtain the proper permissions to setup a private mooring "downstream" and out of the way. Does anyone know if there are many hoops to be jumped through to obtain permission to setup a private mooring on such a river as the Potomac?