What a thread! You guys should rent yourselves out as The Mudcat Fix-It Dudes.

Here's something no-one else has suggested, and it's probably the tack I'd try.

The problem is the snotty neighbour. Whether the law is on your side or not, she'll still be snotty. If it's not the trailer, it'll be something else. SO - the long term solution is to get her on your side. You will have to employ some good acting techniques (and pretend you WANT to make friends) and some detective work. Where does she work? What makes her tick? Is there a charity she's sympathetic to? Does she like little dogs? Collect stamps? Find her weak spot and hit her with it. I've often found with those sorts of people, it's easier to win by APPEARING TO BE ON THEIR SIDE. Maybe a pipe dream, but maybe if you're able to come across as sympathetic on a topic she can understand, the rest would be easier.

Good luck.

Callie