If you want 12v anytime why not just run a fused link straight from the battery? Creating your own subsystem is way safer than messing with such a fragile "e"cosystem that the 4Runner has. IMO
Search around and see what happens when a rodent bites into a harness, let alone you picking a fuse to add-a-fuse to that fries one of some odd 30 f'n ECU's in the truck