I go every year with my old high school buddies. 2 Guys are in the army and just recently got back from Iraq so we usually don't have a say when in the summer we can go. Luckily this year they both are on leave right now which happens to be the high water time out Colorado. The trip runs from 9:00 a.m. to about 2-3pm depending on how fast the river is moving. Last year we went in August when water levels were much lower then this year. If you do the full day trip like we are doing this year (It's only $85 bucks a person), however our guide last year told us that unless the water is really high that the half day trip is the way to go. The reason for this is because the first part of the full day trip is a lot more mild than the second half. But when the water is high the class 2 and 3 rapids on the front stretch become class 3 & 4's and are a pretty good warm up for the second half. The second half of the trip is insane. It should be a lot of fun. Here is the company we use, they are really nice and do a great job:
Performance Tours
My friends and I have only done the Royal Gourge trip but it is a blast, Next summer we are going to do the Numbers trip