If I have to disconnect the trailer harness due to corrosion and am not replacing the harness right now, can I just unhook it from the battery or do I also need to completely remove it from the taillights as well?
You can mount your converter box where ever you like, however, we recommend in a weather resistant area like inside your trunk panels or behind your taillights (If it will fit)
Instead of mounting the socket bracket under the bumper, I followed a tip from another video and ran the socket wires into the compartment on the left side, where the jack is stored. It's easier to get to, and stores inside out of the weather. I ran it through a vent grid below the light. Had to break out one bar of the grid to get the plug through, but it didn't hurt a thing. I'm sure that would also work in a car trunk.
That works as well! There are many different ways to mount/store your harness and for more info you can look it up in this video: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-icxNw94AsFU.html