I get colonoscopies every year, so I've had a little experience with the prep.
For me, the worst part is the liquid diet the day before. I hate trying not to feel hungry when all I can have is broth and jello (but not read or purple jello!) If I'm in a good period with my bladder where I'm not wearing diapers anyway, I usually put one on at noon when they want me to take Dulcolax tablets, since those can occasionally hit me pretty fast and hard.
Usually the main part of the prep starts at 5. I've done most of the available preps out there, but the most common one that doctors seem to use these days is Miralax and Gatorade. That's an easy one - a glass every ten minutes until I've had the required amount. With a Golytely or Nulytely prep, it's the same drill, but the stuff tastes kind of salty, and I rinse my mouth IMMEDIATELY after swaying the prep using a second glass with tap water. I sweetish it around in my mouth and spot it out, then repeat. That helps keep me from gagging on the liquid later in the prep, and it makes all the difference in the world. I actually prefer the Golytely prep, and my doctor claims it's more likely to do a good job.
It usually takes an hour before the Dulcolax from earlier and the liquid prep start kicking in, so I'll sit and read a book, but you want to be close to the bathroom during this time!
Before the first BM occurs, I coat my anus and the surrounding area with Vaseline. That keeps the stool coming out from being in contact with my skin, making cleanup easier and ensuring that I don't end up with a sore bottom.
If it's a split prep (which seems to be the trend - the last two times I've had a colonoscopy, they've requested a split prep) I only drink half the solution, and save the rest for the next morning. They'll give you instructions on what time to start the second half.
Split prep or no, I usually have some anal leakage overnight, so I'll wear a diaper. I also wear one to the procedure, and take a clean one to wear home. I have pretty significant ulcerative colitis, so I don't know if others have the anal leakage issues I do.
The second worse part of the prep is if I'm still seeing any brown in my bowel movements, they typically want me to use two Fleet enemas a couple of hours before the procedure. Those things are uncomfortable at the best of time, and even with liberal use of Vaseline, my bottom is sore enough that they burn going in and burn coming out. But it doesn't take long, and most times I don't have to use them at all.
The colonoscopy itself is nothing. They've finally learned that I need enough midazolam to tranquilize a horse, so they push plenty of meds, and I wake up in recovery. Get dressed, have my wife drive me home, eat, and nap the rest of the day.
