The back walls (the ones with the shelves on them) are 4'6". We wanted to fit at least a 24" wide door, and the size of the side walls was of course dictated by the depth of the adjacent cabinetry. So, a 24" door needs a 26" rough opening, jack and king studs on either side adds 6" more for total of 32" on the 45 degree angle wall, and to fit a 32" wall in between the 2' side walls, they need to be about 4'6" from the corner. Be sure to make the closet bigger if the door is bigger. The favorite thing that clients like about this pantry design is the lighting. We used 24" flourescent lights, one high and one low, just inside the door so you don't see the fixtures but you are able to illuminate the entire pantry.
Thank you for the question and good luck with your project,
Andrew

thanks so much!!

This method of creating a pantry has been very popular because it creates significantly more storage than cabinetry, with easier access and lighting, and it is less expensive than creating the storage from cabinets. It would be possible to add plywood skins and trim to the walls to match the cabinetry and if desired we could use a stain-grade wood door to match the pantry door to the cabinetry as well. I recommend against using a large cabinet door or double door because of the tendency for wood that size to warp.