I have been guiding float trips down the Grand Canyon for some 20 years. By "guiding", I do not mean running a raft, which is the job of the outfitter's crew. Instead, my task is to make the trip as enjoyable and informative as possible by working out camp spots, hikes, and features to see, and by giving talks that explain the geology, archeology and so on in the Canyon. I have done this not only for groups of professional earth scientists, but also for "lay" people who have an interest but no background in such subjects. The result has been the development of what amounts to a curriculum of presentations given in every-day, non-technical language.
Normally, guiding a trip goes with arranging it, but it does not necessarily have to be so if you wish to do your own arrangements, or if you are a party with a private permit. In either case, having an expert along will enhance your trip considerably.
Part of my service is to provide information on such things as what happens on the river, what and how much gear to bring, and so on. You will probably find this really useful, and it will help you avoid bad surprises.