The trailer looks to be in pretty decent condition. Roof leaks are always the biggest problem with these flat top trailers, if they haven't been taken care of.

I bought an older 2 axle trailer about 12 years ago that was pretty well trashed on the inside. I was going to fix it up but I ended up selling it because I no longer had a vehicle big enough to pull it. Now I have a really old "canned ham" trailer that I've been working on for the past few years. I got it cheap, but it needed way more work than I realized when I bought it. I've written a bunch of posts about that over the past couple of years. I'll start working on the interior this coming summer.