6 days in california

Hello, My friend and I are looking to hike in California (preferably northern) for 6 days between - 16-22 May. Starting and ending in San Francisco. We have a car and are looking for a round trip hike, or as close to a round trip as it gets.. We can also split it into 2-3 separate hikes with a drive between them. We can go ~12-14 miles per day. Are there trails you can recommend? Would really appreciate your input! Thanks, Grisha.