If it were my trip, I would leave Monterey no later than 4 am. You need to leave time to drop off the rental car as well as morning traffic and busy time at the airport. Taking highway 1 (not called PCH this far north) is much longer. Take 68 to Salinas and pick up 101 there. If you have access to traffic reports, you can choose between 101 and 280 as 101 is a little shorter.