Depends on how much you have to swap. If all you getting is a bare cab, that's a lot of time to swap everything over. not hard physically but time consuming.
The physically hardest part would be having a few friends over to lift the old cab off and put the "new" cab in place.
I've done it but expect a lot of time involved and plan on finding more stuff you want to fix as you go. Like clean the frame up while it's easy to get to.
I did one about 9 months ago. The hardest part was getting the chassis mount bolts undone. The rest was easy stuff, just get some masking tape and label all your connectors on both sides so you know what goes where. Also, have a pad of paper or a good memory to remember what bolts go where.it really was quite easy, but as mentioned above it's time-consuming and you need a tractor or 4-5 friends to help you lift the bugger. My new wife and I are gonna do one again in a few months, and we're not intimidated at all. Good Luck!