Don't you have a 120 VAC receptacle on the outside of the MH on the passenger side? Run an extension cord from the trailer to that receptacle.
You may need to wire the trailer as you see fit including an external "input" such as this:
Ted & Melinda
2016 ACE 27.1
2016 Chevy Sonic Toad
2020 Chevy Colorado Z71 Trail Runner Alternate Toad