My physician / hospital provided me with a good 'kit' of information pre-surgery which was specific in detailing all of the post-op supplies I'd need - and there are more than one or two. I arrived at the hospital on the day of the surgery wearing sweatpants and continued to wear sweatpants during the 12-day period my catheter was in. I'd alternate with shorts when in the house, but when I'd go for the mail or start to walk in the halls of my building, and outside, the sweatpants worked well for me.
My hospital wouldn't discharge me without my first watching a video on how to care for the catheter, and I was given printed material to take home with me outlining the same procedures. My nurse attached the catheter bag the first time and demonstrated each step, also. The hospital also sponsored a pre-surgical seminar of 1-hour where many things were discussed and questions were answered.
I suggest arriving at the hospital with a shirt that buttons down the front, because you'll have some small incisions that'll be taped and possibly leave with a drain (though mine was removed immediately prior to my departing the hospital). Raising your arms to put on a pull-over shirt could be uncomfortable at first - though after a couple of days I wasn't bothered by it. Also, I wore sandals my feet could slip into, so I wouldn't have to bend down and tie shoes (because I was concerned I'd have difficulty bending down because of the surgery / incisions). The sandals worked well and I was pleased I'd brought them.
My at-home post-surgical supply list included: sterile gauze pads, alcohol wipes, tape, thermometer, vinegar (used in cleaning the catheter bags), alcohol (bottle of it), cotton balls, Q-Tips, stool softener, antibiotic (Cipro for when the catheter was removed), pain pills (codeine to be used only cases of extreme pain - and I never used one of the tablets), Tylenol (for pain relief, and I used it on occasion and it relieved whatever was slightly bothering me), antibiotic ointment (to apply to incisions and catheter tubing), band aid strips, saline solution (for care of catheter bags), Depends underwear, Depends pads, pad for bed (placed under mid-section of body) in case of bed-wetting at night (when you sleep you don't always have control of your bladder - after catheter is removed). I change my pads often, and even when I wear the Depends underwear (principally overnight) I use a pad for added protection. The pads are relatively inexpensive. By the way, I found that the generic pads sold at CVS and Walgreens (as two examples) aren't as good as the Depends brand and I've gone back to Depends because of the quality and better fit. Jockey-type briefs are what you’ll want to have on-hand, not boxer shorts – because the pads don’t work well with the boxers.
I purchased most of my supplies before going to the hospital, because I live alone. On the way home from the hospital I had to stop at a pharmacy to get the prescription items, though - and I had the benefit of a friend driving me. Sitting in the car for the 40-minute ride home and stop at the pharmacy was very uncomfortable, though. You may need to have a pharmacy or someone fill your prescriptions for you - if that cannot be accomplished at the hospital before you're discharged (you could arrange with a nearby pharmacy to do this, before you go into the hospital).
Regarding diet, I stayed on a bland diet - light foods, not much 'heavy' - for the first week, then I began eating what I wanted. My physician has recommended small snacks/meals instead of two or three large meals daily for the first month post-op - and that's what I've been doing.
I hope some of this helps you in the process of planning for your soon-to-be successful surgery.