Seeking trailer selling advice for a fixer-upper trailer

What would I do?

I would give him 30 or maybe 60 days to remove the trailer and after that I would report it to the police as abandoned. The police will arrange to have it towed away and it is no longer my concern.

I had to do it with a car that was left at the house. The police took it away and months later the owner asked what happened to it and I told them to call the police.

Being a nice guy is fine, but don't be a patsy, give adequate time and then take action.