[Reinovator]

swapping cabs can be either a pain or just time consuming. as stated before check with your local DMV and see what they would prefer you do most of them are pretty easy to get along with if your up front and honest about what your doing.

the biggest problem I ran into was not have enough help and not using my head the first time. since then I've learned.

take out what you can put back in easily seats doors glass etc. find a nice 'A' frame or cherry picker adapter. and carefully, slowly lift the old cab off checking for still attached parts, wires cables, move it to the side and reveres your steps try to do it in one weekend, if your like me I for get where things go if you have to take picks of key areas for reference. then transfer back what you can or want from the original cab and go from there.
its really not all that hard just time consuming, take brakes be sure where things go. almost every thing unbolts or on plugs,as said before you can do it.

and don't crack the beer open until your done.
'if you drink'
It's worth the time if you like your truck.
Research your options, maybe even up grade your cab.

I'm doing something similar, and I know I going to run into problems but swapping a 77 PU cab and putting a 87 suburban(panel) body on is a little different. but most of mine is imagination.

Good luck and enjoy it. if you decide to do it.