I just want to throw in a thought or two about rafting the Grand. I have done it twice, both motorized trips. While I would love to do a dory trip, they are (obviously) more expensive, and you spend a lot of time while your guides (and you, if you wish) row downstream, often against heavy upstream winds. If you are motorized, you have fun in the rapids, but you also move fairly quickly from one hike to another, or at least that option is there. While I really enjoyed the whitewater, the things that were magical about the Grand were the side canyons and the little hikes to "surprises" along the river. Your mileage may vary, but that's something to consider.
One of my trips was with Wilderness River Adventures. They had lots of user nights, and not so many clients on my particular trip. I got a good deal by paying at the time I signed up, for a trip that I couldn't change. Then I got trip insurance that included cancellation if something happened and I couldn't make that particular date. There were only 6 clients. We had a great time, and did a good deal of hiking to splendid places. We went in late May. The water was chilly when we started and hot when we ended, but overall, it was pretty nice. You might contact them to see if a deal could be had.
Just my thoughts... Pringles