The butler's pantry sounds great! If you are storing flat items like trays and cookie sheets, try to put in dividers so you can store them upright. It saves a lot of space and makes them very easy to get to. I use a "low tech" version by using a folder divider from the office supply store, but you will probably be able to put in a nicer version while you're installing the butler's pantry. If possible, I would also put in shelves that can be adjusted or removed, so you have more flexibility in terms of what you want to store.
As far as packing for storage, I went through that not long ago when I had to live in temporary housing for a couple of months, while my stuff was in storage. My biggest advice is to try and get boxes that are the same size so they stack easily. If you get free boxes in all different sizes, they will not stack, and it is a real pain to try and store them or fit them on a truck. Boxes start falling over or getting crushed. To me, it's well worth the money to buy boxes (although you might check freecycle - I gave all my boxes away once I unpacked them. You can even have them delivered directly to your house so you don't have to haul them in your car. (I have a small car, so getting large boxes delivered was a necessity.) I used uboxes.com and the boxes all came right to my door. UHaul also sells nice boxes and packing paper. Get a tape dispenser and a couple of sharpie markers, and label everything.
