In my opinion, something having the largest tanks you can find, plenty of room for solar panels on the roof, and space for a good size battery bank (450 Ah minimum).
I have 115 gallons fresh, 65 gray, 45 black. Three weeks is not difficult, four weeks if I conserve. 650 watts of solar provide all my electrical needs.
The rest is pure opinion and what fits YOUR lifestyle.
I prefer my Jeep and bicycles. I don't care for those quad things but obviously a lot of folks feel differently - hardly seems right to suggest that what I like is the "right" approach.