I replaced mine with a repair/remodel box from Lowe's. These have the same type of attachment into the interior skin as the RV recepticals and fit right into the same hole.
I replaced the outlet by the door with a double box with 4 outlets. That obviously did take some aluminum cutting. Now, I can leave my neon phase tester and my voltmeter plugged in all the time and still have free outlets by the door.
John W. Irwin
2018 Interstate GT, "Sabre-Dog V"