Where is the bunker at Fiddler's Green Trailer Estates?

I have found a radio signal, it says:

Anyone out there; if you can hear me I'm trapped inside a bunker in... er, what is this? Fiddler's Green Estates. Got some crawlies outside - it's nothing I couldn't normally handle but I'm nursing a bum leg. Could use an assist

However, after killing everything and searching all of the trailers I am still no closer to finding him.

Where is the bunker at Fiddler's Green Trailer Estates?

Solution 1:

The bunker can be found between two trees in the inner corner of a wooden fence. I know this description doesn't do it justice, so here's a screencap: