Finally got around to removing the battery, the box, the lights & power cable, the breakaway brake cable receiver, and the jack.

Next steps:

Remove hitch ball lock mechanism and clean the tongue inside and out real good, paint it (minus the inner ball area), install new lock.

I'll also apply a thin layer of grease in the unpainted ball area to prevent rust until I'm ready to use the trailer.

The exposed frame will get painted at the same time as the tongue.

I'm also building a new electrical box out of an Iron Mtn data tape storage case.

The case is made of steel. I have to remove the foam padding inside and grind out the middle divider, then add holes and grommets for the wiring and mount it to the frame.
The new battery will be given foam corners to reduce jostling.

Then the brake wire needs to be fixed near one of the wheels.

Taillights need to be replaced and sealed, along with at least one clearance light.

Some body rot will need to be taken care of, too. Basically just planning to knock/grind out what I need to and fill in with foam.

Probably a few other things to do, too. It's taken me something like five hours to compose this thread due to interruptions and my train of thought is hosed.