I see that my name was taken in vain here already so here goes a couple more suggestions from my experience in San Mateo -- You will get several hospital issue underpants, and will wear a pair to your hotel, along with the fresh ones you did not use in the hospital. Have a bottle of hydrogen peroxide waiting for you, and you can clean those in the bathroom sink very well and use them until your packing and catheter are removed three days after your discharge. Have enough of the widest and softest sanitary pads you can find, you will change them every few hours. Double layer is OK, and they fit in the hospital undies quite well. Warning, even the softest will feel like box board though!
Your pre-op underpants are going to be history, so get a couple of 10 packs of Hanes or Fruit Of The Loom cheap cotton underwear to use at home. As Izzy said, one or two sizes bigger than you now use. You will want to change them after every dilation, so they need to be a day or two of supply to keep the washing machine from overloading.
Go to some place like Costco, and get a couple of the 24 packs of Hospitality Grade plain white wash cloths. Those were so much more comfortable for post dilation cleaning and mopping than toilet paper was (and still is at close to 19 months).
I keep my dilator of current use in a clear plastic shoe box along with two clean wash cloths and the lube, and it goes on the bed beside me where I can reach it easily. Last item to pre-stock at home are bed protection pads -- the absorbent paper on plastic type. Get the BIG package for home, and stop at a drug store in San Mateo and get a smaller package to use there. At first you will go through lube like crazy --Wal Mart is cheapest -- but in time it will taper off to just a small amount. I would recommend using rubber gloves for a few weeks at least, the dilator does get slippery and messy.
You are going to do fine there Sis, and I have a lump in my throat knowing I have a new baby sister on the way. (My surgery with Dr. Bowers got bumped up three months as well.)