What you want is Select-trac. The Quadra-trac is the Full Time that came in the grands, with the not-desirable NP 249 T-case. You're always in Full Time, no 2wd option, and the viscous couplings for the front like to stop working.
Select-trac has an NP 242. It gives you 2H, 4H FT, 4H PT, N, 4LO. It also has a geared mechanism for the Full Time that's not prone to failure. You also get the 4 HI Part Time option, which is desirable over Full Time in some situations.
4x4 swaps are really easy and completely bolt in. Do a quick search, you should find plenty of threads with lists and details of what you need.