Can u please help me plan my trip Portland, OR and Crater Lake?

My friend and I plan to go Oregon for the first time. I really wanna go to Crater Lake. we gonna rent the car and drive there. I am flying from oakland, CA to Portland, OR. we have only 4days and 3 nights. we are planing to go on july 25 and back on july 28. Please help me plan da trip. thanks guys