You can't camp near the trader, this map is STUPID fun and involves a lot of running away for the most pat (unless you hide on the roof of the little shanty like a loser). The trader offers no cover at all. You need to keep moving.
That said... I have some issues with this map. It's awesome, no bugs at all. Damn near flawless and I enjoy playing it, but once I get a number of enemies up and running around... my FPS takes a dramatic bomb. It happens on this one and KF-Marshes, but not on any other map official or community made. Any ideas as to what could be causing it? Once the wave goes down to just 1 Specimen left my FPS goes back to normal. It's pretty confusing and any insight would be great since I love the map.