Water capacity & battery capacity are king when it comes to dry camping. Figure out your cube & you can get an idea of how much tankage you can put in there.
When 5er shopping if it did not have at least 80 gal freshwater capacity the model was taken out of the list of possibilitys. That cut the size of the herd down real fast. We have 100gal capacity. So nice to be able to do at least 4 nights with 2 of us & not break a sweat worrying about water.