There are several members here with a '58 Overlander who would have more info than me. Hopefully, they'll chime in. As always with a trailer of this vintage, check the interior's perimeter as it meets up with the walls especially around the entry door and sinks. Check to see if all of the window frames are in place, both the stationary ones and the moveable ones as well. These are next to impossible to find. Don't worry about the glass, its flat and can be easily replaced. Check the ceiling vents, breaker box and appliances. Closely inspect the frame as it comes out of the belly pan at the front and rear for serious rust. Surface rust is treatable but the frame rotting stuff would scare me away. You'll get a sense of its treatment over the years within a short amount of time and take your time with the seller. Ask lots of questions.
4CU 2699 / AIR 10 / TAC AZ-1
I'm haunted by aluminum.
Charter Member of the 4 Corners Unit.