Modified ATC Setup
Ben from ATC installed two eyebolts in the back of my 03 Taco and bolted the front to the bed. The bolts are ok if you don't remove the camper from the truck. But I just load it for my weekend trips, so it's not very operational with the bolts. It's almost impossible to line up the holes.
Now I use some 8" of chain on the original Toyota eyelets in the front of the bed with the turn buckles going to the corner brackets. Chain and turn buckles are at an extreme angle, which I don't really like, but it works and is holding up fine. For off road I think I would use again the bolts in the front, just to be sure.
The back of the camper is held down with turn buckles to the installed eye bolts.
If you need pictures let me know. I took a few of Ben doing the installation on my truck a few months ago.