Welcome to the site. I have built my own gun cabnit but no plans. Just played it by ear. I like cabnits better than safes, seems this country is in one hell of an uproar over everything anymore. I took a different attitude and taught my kids about guns. Would send you a photo but haven't re-done it yet since my house burned.
Just keep in mind, your building a box to keep your guns in. Take it from there.
From the books that I have read, there is a lot of importance in knowing every nook and cranny of your hunting territory as well as the animal that you are hunting. So scouting as much as possible, just walking the land, will give you a good idea of what's around the corner or what's on the other side of a hill. Which can be very beneficial.
Making your own maps of human and deer trails, and different types of foliage such as group of pines,...