You can test the propane for the range and the city water connection from your own hose. For the propane tank, remember "righty=tighty, Lefty-loosy". Turn valve till it stops to open. Get a small propane lighter, like for a bbq grill, turn on one stove burner and keep the lighter flame over the burner till ignites, then do same for other two. Remember you must have an open window when burning propane at the stove, or it will suck all the oxygen from the surrounding camp air.
For city water, first open the grey water drain cover outside of camper, attach hose outside camper to city water connection and turn on hose. Inside camper, open first the cold, then the hot faucets, allow all air to escape each faucet so you have a steady stream. Keep the hot side running 3-4 minutes which allows it to fill the water heater tank, 6 gallon capacity usually, then look for the switch under the bench that has a little light cover next to it, that is the hot water heater ignition, switch it on and wait about 20 minutes for tank to heat up. You need battery hookup for that switch to work. Your overhead lights are on battery too as you probably already know. Others can chime in on how to test the furnace, A/C as you may need more than battery power for those. Turn off propane bottle when all done checking and remove one battery lead for storage as the CO detector will draw power otherwise.
Dobe Fanatic - Largo, Florida
2012 Flagstaff T12RB A-Frame