Congrats! I had surgery with Garramone last June, so while it's a been a year, it's still kind of fresh in my mind.
Nygeel is right--button downs are essential for the first several weeks. Don't even try putting on regular shirts. Lifting your arms above your head (or even greatly from your sides) is a big no-no. Bring easy to put on pants like scrub bottoms or sweats; slip on shoes are also good. Wear or bring socks with you to the surgery center, it can get rather cold.
Extra pillows are a good thing. My back hurt a lot from the bandages being so tight (I loosened them with permission). Bring something to keep yourself occupied like books, handheld games, movies, etc. Don't be surprised if you end up sleeping most of the time. Most people have some degree of pain--stay on top of it. Take your antibiotics and pain pills as directed; the antibiotics are incredibly nasty tasting and smelling so I ate them with jello and held my nose lol Publix (a grocery store chain) has a pharmacy where you can get the antibiotics for free. Without insurance the pain pills cost less than $20.
Showering and/or bathing is not possible until after your bandages and drains are removed. I wouldn't even recommend sitting in a tub mostly due to having to get in/out would be too taxing on your arms/chest. Soapy wash cloths and baby wipes are good alternatives. My mom washed my hair over a sink as well. Constipation can be an issue with the pain pills and the anesthesia; a stool softener like Colace can help.
Since you are traveling by plane, request a wheelchair ahead of time on your return ticket. It was a lifesaver for me. Bypassed the security lines, got zipped around the airports, and got excellent seating. Plus my pat down was so minimal it was ridiculous. Ah, the pat down. Because you can't raise your arms above your head, you can't go through the body scanner. Garramone will give you a letter that explains all of that to the TSA (airport security) people. The letter doesn't out you so how much you elaborate is up to you.
A good diet before and after surgery would be great. Staying well hydrated and being in good physical condition are also important. Sometimes the anesthesia can cause nausea. Having bland foods available as well as clear liquids (which includes jello and broth) can help. Bendy straws are awesome.
I realize this is getting long and I'm sure that I've forgotten things, but this should be enough to get you started. If you have any answers feel free to ask in the thread or PM me