It really depends. If DL is the early entry, you can probably hit 2-3 rides in that 1 hour. However, keep in mind where in DL you are and you still have to walk to the front gates and get through the people coming in, walk across the promenade and get in line at CA. But you may be stressing too much to get over there and not enjoy the scenery as much! CA is a spread out park so if that is the early entry, you may only hit 1-2 rides before having to head over to DL. In my experience, both parks are at their lowest crowds in the first 2-3 hours. So that's always my goal time frame. I get fastpasses or ride my favorite rides in those first few hours with little wait times. By 11AM both parks start to get busy.