One repair I've done is to run weather stripping around the escape and mangers doors to try and prevent water from leaking in and causing rust. I also ran silicon around the gap between the wood that replaced the rust out mangers to prevent hay/grain/dirt/water from entering the dressing room and causing the wood to decay and the walls to rust.
I also ordered butt bar covers to give Stella something to poop on, I mean lean on. I still need to do another coat of the rust paint on the roof as well as the rest of the metal parts, and I have a different paint for the wood on the walls and divider. I think the paint really freshens the trailer up!
Something I had done was have the trailer rewired. Most of the wiring was circa 1980s and some of the repairs were very hack job and "creative" I.E. housing conduit to attempt to rewire the brakes.
In this picture you can see some of the rust on the plug, as well as the housing conduit spliced into the trailer wiring harness. Yikes!!!! I think this was done when the axles were replaced on the trailer? The rest of the wiring appear to be original.
Here you can see the corrosion on the trailer plug, as well as what was supposed to be a temporary until we can get a better repair done job splicing the wiring together.
I purchased the main wiring harness at an RV place, although it would have been cheaper but slower to order the part online, and I bought the wiring by the foot at Home Depot.
All of these repairs were necessary but not an emergency (although the wiring really needed to be done) and were mostly hidden when I purchased the trailer. I have a few other things to do over the summer to freshen things up a bit and I'll post pictures as I do them.