on the Lot my brother and I built in Mountains of Central PA I ended up installing a "penn state privy" basically a 1000 square holding tank with an box with toilet seat mounted over a hole on one end that is vented to outside.
We covered the whole tank with a 68" x 98" shed so we store stuff in it.
I installed a 4" chimney to vent the tank to outside, than added a 120v radon van to this vent stack.
first time I used it you set on the seat with fan running and the wind would just about suck you down and seal you to the seat, so I put a high current dimmer on the radon fan to slow it down :).
at the final inspection the the inspector said "I don't want to see you bury a pipe from that RV to the holding tank". so we use a blue tote instead :).
with 3 or more RV's using this we can go 2 years before the tank gets full enough. We know its time to pump out the tank if you get hit by "splash back" when using the inside seat :(
at new home I live uphill from street so I can use a masarator pump, but its just as easy to drive a couple miles down the street to use the local campground (that charges $20.00)
my RV storage area has a what looks like a sewer clean out right next to this building that is on the property. the building has a toilet so this clean out drain must work. I know the water there comes on.
I keep forgetting to ask the guy that run the RV storage committee about that.