We just got back from the identical trip a week ago! We ended up having to drop Page, though, because of a last minute delay in our plans. But, I decided (mostly bc of budget) to drop the raft in Page because my youngest was 5, and some reviews made me believe they would get bored after awhile... The reviews were unanimously positive about how beautiful it was, but I think it's 2 hours of the same view. If budget were not a consideration, we would have still done it. Other than that, we were doing Lower Antelope Canyon because it seemed more exciting for the kids. Again, with an expanded budget, we would have done upper and lower.
Are you going to Page first? If so, then our itineraries would be similar. You could drive into the East entrance of the GCNP, and then just stop at all of the outlooks. When you go into the park, they'll give you a map with all of the stops. We probably stopped at about half of them. Definitely hit the Desert View Watchtower and the one with the little museum. So, we took a couple of hours to drive from the East entrance to the South. We stayed at Yavapai Lodge (hope you were able to get a room inside the park!). We checked in and then ate at the market place there. It was pretty crowded over Easter week, we just had no interest in waiting for a table at one of the sit downs. The prices were perhaps a little better than Disney counter service. They also have a pretty decent grocery store if you want to buy things, it wasn't as expensive as I thought it would be. For dinner we ate at the Maswik cafeteria. Lots of variety, and it was decent for the price.
For hikes, we stayed around the south rim. We went down in the canyon on the Bright Angel Trail. We didn't go all the way, though... DH and my middle son were not fans! But my other two and I thought it was great. We also just walked around the rim trail at a few different places, just stunningly pretty. We watched sunset at Yavapai Point. We are from the Deep South, and we were unprepared for how cold it became!
When we left GCNP, we drove through Williams, because we wanted to jump on Route 66 a bit. We stopped there and just walked around a bit, peeked into a few shops, and had lunch at Goldie's diner. The food there was pretty ok, but service was sloooooow, and it wasn't that cheap (but, not expensive, either).
If you aren't interested in that, you could go back to Hwy 89 and stop at Cameron Trading Post for lunch, and Sunset Crater Volcano and Wupatki (ruins) were very nice stops. We spent about an hour at each walking around.
I don't know where you're staying in Sedona, but I highly recommend driving in through Oak Creek Canyon, it was so pretty!
We decided not to do Pink Jeep Tour because we could rent our own jeep for 24 hours for the price of the Pink Jeep Tour. We drove 4 different trails, including Broken Arrow, and we were able to stop and have picnic lunches in the most beautiful places. It also helped us to see so much more than we could have if we were just hiking all of them.
Devils Bridge was a major highlight. Be prepared for some semi-rock climbing! Chapel of the Cross was very neat, Bell Rock was a fun climb, but you're in full sun. Our absolute favorite was Cathedral Rock! We all climbed pretty high up, then DS 13 and I went almost to the top... It was very strenuous, but so much fun! We also enjoyed some easier hikes... Baldwin trail, for example, led to a stream where the kids played in for hours! Trip advisor has a wonderful forum if you want to ask specific questions about particular trails, and we went on many if you have other questions.
We ate most of our meals in the condo in Sedona, but we did go to Elote, which is so highly recommended on TA. It was good, but I did not think it was worth the hype. And, while it wasn't especially expensive, it was still a pretty pricey meal for a family of 5. I wouldn't do it again.
We would have done Slide Rock, but it wasn't warm enough for us.
Let me know if you have any questions. It was an amazing trip!!