Couple good ideas above. I actually thought of doing something like the door John has. The cable pulls/pushes are very difficult so I plan on opening the bottom and inspecting the cables and valves anyway before deciding on the electric valves. Btw, I don't see the wiring as very difficult. I would have the area open, so running wires would not be much of an issue.
Below a couple links to examples.
John
https://www.etrailer.com/RV-Waste-Va...iABEgIuuvD_BwE
https://www.amazon.com/Barker-24130-...67465778&psc=1