It depends on what you like to do. The park is big enough for ten days of hiking, in desert canyon country. There are at least a dozen different trails, and you can get a back-country permit, but they still want you to stay on trails so as to not destroy the desert biology in undisturbed soil.
I could stay busy for weeks trying to map the geology, except I would not really be allowed to get around to do that, considering the restrictions that protect the park.
Bicycling is on-road only, so not a place for mountain biking. But some of the road loops are 30, 60, 80, 120 miles, enough to keep a road biker busy for several days.
No water sports, no theme park rides. Grand Staircase nearby, and national forests for more open recreational activities, still mostly hiking and limited to established roads.
Capitol Reef is a quite long linear park, with limited internal roads, connections by highways outside the park. Staying there 10 days, I would probably be thinking about using more than one campground location, for access to different parts of the park during my visit.
But generally, when I am thinking about "things to do" a tend to prefer National Recreation Areas over National Parks. NRAs are about opening lands to access, national parks have been moving more in the direction of protecting the lands, limiting activities as necessary toward that end.
Tom Test
Itasca Spirit 29B