Same on my Winnebago. We tend to dry camp a lot so what did was to use the winterization siphon hose. My tank is right under our bed, hose easily reaches a 5 gallon jug.
At least in my case I don't think I could just dump into the tank through the hose attachment, even if I flip the to fill position. I suppose you could try it and see if it works in your case. Need to place the jug on a ladder or something higher, which I've done with the gravity fill types.