I have all the parts at home for my NP242 transfer case rebuild. Got the rebuild kit and chain from Summit Racing.
Lots of YouTube video's on the rebuild. Its not like rebuilding a diff and doesn't require meticulous set up. Just pull it apart and replace all bearings, seals and chain.
I did buy myself a stumpy 14mm ratchet ring spanner to get to the top bolt.
I have not done the job yet, but apparently the transfer case is a lot lighter than the auto transmission, so one person can get it out easily enough and rebuild it on a bench.
Heres a NP241 rebuild which shows you how easy it is.