First thing I'd do is put a protective cover on that hi-lift back there. Then get rid of those automatic locking hubs and replace them with some good manual ones. Then put a stick-shift under the truck
Replace the t-case with a manual one at the same time. Some nice additional forward lights (you decide what you need based on how and where you drive), something better than factory for backing up as well. Front trailer hitch receiver would be pretty much mandatory, seeing how these trucks have exactly zero recovery points to hook for when you get stuck... Plan on a 9k winch on a receiver-mount cradle down the road, very very useful to have for all sorts of tasks. Obviously feel free to rearrange the list in whatever order suits you better.
No help on the rack, sorry, don't wanna give you bad advice that results in the topper cracking.