Explore a national redwood park just a short drive north of the Golden Gate Bridge. This does require a reservation, so plan in advance.
Explore the Tomales Bay area and taste the ocean in the freshly shucked oysters of Hog Island Oyster Company. This was a day adventure that Steve and I did on our 4th date.
If wine is one of your passions, consider driving up to Sonoma Wine Country and explore a little of the hundreds of wineries this region has to offer. If you want to fully partake in the wine and not worry about driving, you can book a tour with one of our good friends and have a sommelier guide take care of you for the day (either in sonoma or napa): https://www.maxnapatours.com
Drive either north or south along the Great Pacific Coast Highway from San Francisco to experience a portion of the majestic California coastline