You can use the Woodworking Table located behind Matthew ( -1642, -533, -2380 ) /waypoint -1642, -533, -2380 and he will also sell you fuel.
Place the trap at ( -1251, -539, -2196 ) /waypoint -1251, -539, -2196. There is a green sparkly at the location but it is very hard to see. You can complete the quest even if you can't see it because if you are standing at the right location (next to the tracks, on the opposite site of the rock), when you move your mouse around, there will be a place where you get a brown popup box which says "Convenient Site. This would be a good location to place the monster trap." I tried a variety of display options (Balanced/High Performance/Very High Performance/Extreme Performance), and I could only see it on Extreme Performance.