The style of quick connect receptacles used in RVs are prone to loosing the connections.
If you have one of the small circuit analyzer, try plugging it into receptacles on the circuit. The wiggle it agressively side to side. Watch for the LEDs to flicker.
Many times once you locate problem receptacle, you can re-pressure the back into place and make it work.
You cannot replace many of the receptacle as they are not installed in a box. Walls may not be thick enough to install standard boxes and receptacles. may not have sufficient slack in wire.