7 weeks is fine. You can do a ton in 7 weeks. Obviously you will always miss some things along the way (you don't have 7 months, after all), but there's no reason to feel rushed when going to the Pacific coast and back with 7 weeks.
Last summer I stayed in Yosemite for a week, even though up until 2 weeks before the trip I had no reservatrions there. It can be done. In the last 2 weeks I snagged 2 nights (Fri & Sat) in 2 different valley campsites. On Sunday am I drove to a first-come CG, Bridalveil Creek, and booked in for 5 more nights. I got to spend a lot of time enjoying sunsets at Glacier Point.