RE: backup monitor
BE aware that newer Ford chassis Class Cs with LED marker lights have a separate marker power supply that is around 11 volts and will not reliably drive wireless backup cameras tapped into them.
RE: Towing 4-wheels down.....braking required for vehicle?
The thing is, your state may not require braking on a towed vehicle depending on weight but there are plenty that do. That law is not a reciprocal one so if you get in a wreck and your equipment does meet the requirement for the state you are in, you can be in serious financial and legal trouble. Not worth taking the chance!
RE: Water inside refrigerator
Put that little plug back in and be sure to regularly clean it. It's primary purpose is to block insects who smell the food and take the highway to it...