Heck it's free, I say take it. But, I'm a caveman and live in the country. My friends and I have taken old Travel Trailers before for free. Junked them out. Turned the frame into a snowmobile trailer. Sold the appliances out of it. And made Cash.
That being said. Without seeing it I can't say for sure. My 22 year old TT has a few soft spots in the floor and I just keep using it. The floor doesn't seem to be getting any worse. It just wasn't supported good enough.
But, if you have soft spots from a leak you need to fix that leak first. I had a older Travel Trailer once that had a leak and a very soft floor. After fixing the leak I was able to lay 1/2 inch plywood down over the origanl floor and then I put down some cheap discount store tile on top of that. I used it for years that way and nobody ever noticed.
It's all up to you. But, you can't take it to be repaired. They will rob you blind. If you have some handy friends who are good at this sort of thing let them take a look at it with you and then decide.