Newbie with electrical problem.

I'll tell you exactly what the problem is. All of your outlets except those in the kitchen are daisy chained from the breaker panel to the first one, then the second one etc. Start at the breaker and be sure the connection is clean and tight. Move to the second outlet and do the same. Keep moving around all of the receptacles until you have checked all of them. Next, connect the power back to the trailer and start taking voltage readings. This is not rocket science, but it will take some time and patience to find the problem. When you are checking wiring be sure that the insulation is not being clamped on. Have seen that a lot over the years and it always causes problems sooner or later.