Sending you comfort as you approach your surgery! I wrote an update post not too long ago that you might enjoy reading. It tells my experience. Yes, it was painful, but there are meds for that. I felt pretty terrible at times, but my doctors told me you have had major surgery, patience. I had a catheter, because I had an epi-dural. The catheter stayed in until the epi-dural was removed.
I'm sensitive to foods. I did the low-residue diet and if I was in pain, I didn't experiment with foods, but ate soups, rice, Jello, drank Gatorade. I cannot eat ice cream, at first couldn't eat chicken, but now can, and I think dairy is a problem. Ice cream definitely is, since I had severe stomach pains after milk shakes, tried at different times of recovery.
For pain, I didn't do well on percoset, it made me miserable with nausea. Norco has worked for me, but I have to take miralax too.
I hope that helps. Please let us know how you are when you are able.