As said above, depends what you want to do with it, if its for tools, just bolting down a tool chest with a lock and drawers would probably do....
I was planning to put a smallish boot build in mine before I did my back in, was planning on building into the back half of the boot, allowing me to keep the dickie seats.... probably bolting the highlift onto it on the side facing the back and having flaps on top for access.....