79 K5 with automatic and locking hubs has two high, two low, and neutral on the 4wd lever...is is best to run on the road in N or H2? Hubs unlocked on the road.

 

It sounds like you have the NP203. If that is the case, then it should not move if the hubs are unlocked with the shifter in LO, N, or HI (none of the LOC positions) if all stock in the transfer case. If you have the NP205 transfer case it should have a pattern of 4LO, N, 2HI, 4HI with 4LO being all the way forward. If you have the NP203 full-time 4wd transfer case that has been part-time converted, then you will have a shift pattern of LO-LOC, LO, N, HI, HI-LOC which will translate into 4LO, 2LO, N, 2HI, 4HI with the part time conversion and having the front hubs unlocked when in the 2LO & 2HI positions

With the NP205; for normal, everyday driving unlock the front hubs and drive with the transfer case in 2HI.

If you do have the NP203 transfer case, you should drive in 2HI (HI - no loc) with the front hubs disconnected. If your truck doesn't move in this arrangement, you do not have the part time conversion. Even with the part time conversion, you should put it into one of the lock positions every once in awhile to lubricate everything properly in the transfer case because the drive chain does not rotate when in the 2HI/2LO positions with the front hubs unlocked.