Are you flying? If so, make sure you pack at least 2 extra outfits for the baby and one for you, plus 1 diaper per hour of flight. This may sound like a lot but it will save you if there's delays. I can tell you by experience that diapers are hard to find in airports. Pack a lot of easy outfits in ziploc bags for the trip (the bags are great for throwing the dirty one on), specially if you are not planning on doing laundry. I did ship wipes/diapers and other baby things to Disney when DS was still little (although not an infant). Remember that an infant goes through ~10 diapers a day. It makes sense to have the space on the way back, but you may have to consider the weight if you are flying, wipes and that many diapers are heavier than clothes. Don't forget desitin, baby shampoo, cortisone cream and baby tylenol. If you have one, a foldable sink tub is a great thing to bring and doesn't take much space (like a Puj tub). Another must for baby travel for me are the munchkin diaper bag dispensers, sanitizing wipes and lots of hand sanitizer. Make sure you have nice change pad on your diaper bag.
If you are nursing make sure you practice doing so with your cover or carrier in public places, but remember the baby centers always have a breastfeeding area, which is a nice place to take a break anyway. Make sure you have lots of snacks for you and a good water bottle, you are making the baby's food after all.
Bring a waterproof pad for whatever the baby will be sleeping on, plus a couple extra ones you can place anywhere, like the stroller/car seat. A blowout on the stroller when out and about is not fun but easy to deal with if all you have to do it take the pad away.
I thought that the stroller seat could not be used until the baby is 6 months, are you using your citi mini with a car seat? At that age I used the bassinet (if you have one). It is a little inconvenient to carry around (mine folds flat at least), but it really pays off to have a place for the baby to sleep anywhere that he is already used to, plus you don't need to borrow a pack and play. Have fun!