Travel Trailer Rubber Roof Repair Options. Help needed ASAP

You would be lucky to get $2-3k on a 2001 26' trailer in decent condition.

Replacing the roof is likely a $4-6k if it turns out to be fairly simple to fix. It could be a lot more if the rot is bad.

If you have the skills and want to put in the effort, you might be able to buy the materials for $1-1.5k and do it yourself.

Nothing you slap on the top will fix the problem if the plywood underneath is rotted out.

Sorry, but no good news.