My first and only colonoscopy was last month. Procedure is nothing. As others said the prep is not fun. My instructions included liquids that are not red or purple up to midnight before and clear liquids up to 3 hours before. Keep your blood sugar and calories up and you will be much better. Hard candies, ginger ale, chicken broth and sport drinks are your friends.
There were two different options for cleansing prep drinks, go with the smaller volume option. I had to pay like $75 more for it as my insurance would only pay for the cheaper one, but it was well worth it. The cleansing stuff tastes terrible.
Plan on sitting on the commode for 25% of the time once you start the cleansing.
My test was clean, one small polyp removed was in at 8 am, out by 10:30. Was woozy til about 1 pm coming off the sedative. By 4 pm i was fine. Signed up for a 100K bike race on the next day that started 23 hours after colonoscopy and did not have any effects of the procedure.
Good luck hope all goes well.