Some use multiple hand carry jugs like shown in previous posts. I bought a white, plastic, 55 gallon drum formerly used for Mountain Dew syrup at the convenience store. I cleaned and sanitized it. I bought a 12v pump and made a pvc dip tub to go into the drum. The pump has male hose fittings on the inlet and outlet. Hook a water hose to the outlet to fill the camper and hook the 12v to the truck battery to run the pump. One trip to the water supply, I'm done in 10 minutes tops. The 55 gallon drum will fill my fresh water tank about 1 1/2 times.
FYI, most RV manufacturers stated fresh water capacity includes the hot water tank.