Glad to see that you have her home and are ready to tackle stabilizing and restoring.
The floor, if solid, is a rare one. If so, you can consider
CPES to stabilize it and stop any more rot. To be clear, it will stabilize good wood, not turn bad wood into good. If you have a small, bad spot, you can consider West Systems Epoxy with or without glass.
The biggest issue to consider is how solid the frame->wood->u-channel->shell structure is. This is critical to the longevity of your trailer. Somewhere amongst
these threads is a great drawing that explains the structure. Sorry that I didn't keep the link, but I think it was NorCalBambi who posted it.
There are two problems in a '59 that will compromise that critical structure -- wood rot and galvanic corrosion. Unfortunately, the drawing will show you that the bellypan goes underneath the outer skin, buck riveted as part of the structure and also held in place by temporary rivets. It's not only the most critical part of the trailer, but the most difficult to repair.
The electrical circuitry is very basic. There really isn't much inside those walls and the wiring may be corroded, rodent attacked or both. If you are lucky enough to find a trailer that hasn't had rodent infestation in the walls, you might be wise to carefully hide new wiring inside the cabinets without taking off the walls.
For your sake, I hope you found a gem that doesn't need a lot of deconstruction before rebuilding. That said, they are time consuming but worth the effort.
Good luck. My advice is to keep posting questions and reading threads. Many have gone before you and have documented their work very well.