Dream: Sounds like a good appointment and a good doctor! As for the prep, first of all it's best if you eat lightly for a few days beforehand, so that there's less stuff in your intestines that has to come out. Make sure to have lots of clear liquids available since you aren't allowed solid foods while doing prep - the last time I did prep, I had several flavors of jell-o (make sure you check what colors are allowed - I wasn't allowed anything red or purple since they can look like blood in the intestines), chicken broth, flat ginger ale (you can also do clear sodas like sprite/7up), gatorade or pedialyte, water of course, and sometimes things like tea and coffee are allowed too (again, check with the specific instructions you get - every doctor/clinic is a little different with what they allow). Make sure you have things to keep you entertained like a book or a laptop computer, as you are going to be spending the majority of the time on the toilet!
What type of prep are you doing? I've only ever done the Gatorade & Miralax prep, which was fairly easy to get down but I always get too dehydrated when I do it, so whenever I have to do prep next they might force me to do Go Lytely instead, which I understand is just vile. Drinking the prep and spending hours on the toilet is the worst part, though. The scope itself is really easy, at least that was my experience. They give you great drugs. I had "twilight sedation" which supposedly meant that I'd be minimally conscious and could respond to orders to roll over or move a certain way, but honestly I felt like I was out completely and I don't remember a thing! I remember they put the drugs in the IV, then it felt like I took a lovely nap, and I woke up feeling pretty great. I was in quite a bit of pain the next morning, but I think that was partly because they had taken a bunch of biopsies, and partly gas pain - they pump air into your intestines when they do the scope, so be prepared to fart a LOT afterwards!
Good luck on Friday, let us know how it goes! I hope you get some answers!