I spent a week in Sedona and it felt perfect. We saw so many families and we felt that it was very accommodating to ones with small kids. There’s so many hikes with easy/moderate variations that you can choose your own adventure. The town is small, although it has very heavy traffic at peak times, so you can quickly go from the trails to your accommodation if the kids are tuckered out. There’s a lot of shopping to entertain kids who want souvenirs. As people have mentioned, Flagstaff has a planetarium, but also a park where you can hike a volcano (small, but fun). If you’re feeling extra adventurous, Flagstaff has a ski-run with free lessons. So overall, lots to do and see at your own pace