Well, you can't hang the cabinets until you get the rock up and finished, so let's start with that.
If the walls aren't down to bare studs, get them that way. Drive in or pull out ALLLLL the nails, insulate as needed and now you're ready to rock
. OK, I would suggest hanging horizontally. I would also suggest getting rock long enough and wide enough to cover each wall with only 2 sheets (one seam). Sometimes, obviously, this isn't possible, but if your wall (any given wall) is less than 12 feet long, and less than 9 feet high (yes nine, that's not a typo. I didn't mean eight ), you can rock it with 2 sheets. They make 12 foot drywall, available at any self respecting lumber yard. I would recommend against a homeowner and a buddy or 2 trying to hang more than 12 foot rock. They also make what's known commonly as "stretch rock", it's 54" wide (instead of 48), making it possible to rock to a 9 foot lid with only one seam. The stretch is a little harder to find (read that as: you won't find that at the big box. Go to a REAL lumber yard.) Well, that'l do for now.
HOMEWORK :D : Post back room dimensions, lid height, and shop around and see what lengths rock are available in your area, and also if stretch rock is available.
We'll get to the cutting and hanging after you have materials on site. One step at a time, this isn't going to happen overnight no matter what you do, and definately not if we rush things and I/we over-assume. You'll end up doing it twice or three times.
In reading that I guess I may need to explain one term I used that may be puzzling (or may not). Anyway, "lid" is the ceiling. I'm sure you would have figured it out, but now ya don't have to. :D