Best dump hose length

We volunteer and have more than once found that whoever built the sites had never RVed. At a couple we have had to both use extestion cords for the electric and 25 ft to the sewer and be carefull of the slope. We have run into where we could reach the electric and sewer but needed additional freshwater hose.
Normally only need 1 of our 2 15 ft sewer hose and our normal fifty amp electric cord we also carry a 30amp extension cheaper and lighter than a extra 50amp that you may use infrequently.