The clips are definitely going to be real tight on there as it's the first time they'll be coming off. Once you get the screws around it and around the hatch, you should be alright to get a trim tool and slowly get in there.
Ahh, well that explains it. The three previous trailer hitches I installed (one on my wife's Encore) involved being under the vehicle and having to tighten the nuts while on my back. So I understand where you're coming from now.Mine must have been the Curt hitch as the bumper did not need to be removed