When I lived in the Springs, I trapped 27 coons, 12 skunks, and 2 foxes in a 4 year period. I always used a similar trap to yours with a dish of dry cat food. I kept it uncovered except for a 35lb weight on top to keep the coons from dragging it around. Trap size and location didn't seem to matter - I had one bore coon that barely fit in the trap - couldn't turn around. He did manage to roll it 60 feet across the backyard, and popped several welded wires, but it held him. I tried tuna fish at first, but our cat kept getting trapped - he didn't mind spending the night in the trap for a can of tuna.

I slapped together a plywood box to place over the trap for when I got skunks inside. It was just bigger than the trap, open on one end for releasing them back out the door, and open on the bottom for slipping it over the top of the trap. I cut out a hole in the top of the box for the trap handle. If I was slow and careful slipping it over a skunk, they usually did not spray. If they did, it was contained and they had to marinate in it until I released them. I'd just leave the box outside to air out.

You will not likely get rid of all the critters - new ones will just move into the territory. Best of luck.