Q. Can one use a parked camper, motorhome, RV (recreational vehicle) or sprinter van or bus on Shabbos or Yom Tov, that has living quarters including bed, kitchen sink, fridge, freezer, oven, microwave, bathroom and shower, cabinets for storage. It is a vehicle that one can live in with the comforts of a modern home. It has hookups that connect water, electricity and waste for any campsite. 
When one opens the doors, sleeps, eats or opens sliding doors, he does not cause light to come on.
You can turn on the water pump before Shabbos, toilet is not electrical.
A. On question 1180 in regard to climbing on Yom Tov or Shabbos on the back of a (parked) pick up truck where one build a suka when traveling and eating there. Or opening the doors of that truck if the light does not go on, or if one can push the truck (when in neutral) to a better location, in a fenced lot, we wrote:
“Shulchan Aruch (O.H. 624: 2) rules that one is allowed to build a suka on top of a “agalah” or carriage as long as it is firm enough to survive an ordinary wind. Mishna Berura (ibid. 10) also mentions to be careful that the suka should have the right dimensions.
Horav Shlomo Miller’s Shlit’a opinion is that in order to open the doors of the truck on Shabbos or Yom Tov, you may have to disconnect the battery of the vehicle since besides the lights some other unseen functions may be triggered by opening the doors in a modern computerized vehicle. (including security and temperature sensors, heating and AC controls, GPS, clock, and other indicators).
He also maintains that when needed one may push and move this truck to a desired location. (one should be careful not to press on the brakes, as the back lights will go on)”
Horav Shlomo Miller Shlit’a opinion in your case is similar. However, if a water pump is needed for the water to flow from the RV water storage tank, when one is not connected directly to the water provided by the campsite, even if the pump is left on before Shabbos, it may not be used since it will turn on when one opens the water tap.
Some of the more expensive models, have other automatic features, such as seat recliners, heated or cooled cup holders and other gadgets that have to be disconnected before Shabbos.
Because of the complications involved in the use of these modern vehicles, the Rov advises not to spend Shabbos or Yom Tov in them. In case of need, one should thoroughly investigate and understand the unique features of his particular model and how they work, as they do change from one type and model to another. Obtain the necessary information and diagrams, and then consult with a competent Rov.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a