I agree with the other guys. If you're looking to get a trailer and just take off without any worries, yes, walk away.
But....If you're a do-it-yourselfer and in no rush. Maybe point out the pitfalls of the trailer and get a better price (much better). I'm thinking water migration has wicked up the walls from the floor and the wood framing.
Once you open the TT you might be surprised in a good way or surprised in a bad way.
If you actually like the trailer make that offer that suits YOU best. The seller can always say no. What ever amount you don't spend on purchase can go towards repairs. The sad thing is: you won't know how bad it is until you buy it and open it up.
I suspect you'll spend more on time and effort than you will on materials.
Or, make that low-ball offer and tell the seller if he hasn't sold it, then this is my (your) offer. It's your call.
Keep us posted, I think a few of us are curious. Many of us here love the older trailers. Mine is a 1985 and love it to pieces
Jerry & Debbie
Ford Explorer 4.6 Triton V8, AWD, 4x4
1985 Sunline Saturn T-1350
Ham radio VE3JCJ, VHF, UHF and HF