I'm coming with my husband and love finding things to do that I didn't expect to be able to do with a wheelchair.
Oh, lots! For starters, Golden Gate Park is just amazing, with lots to offer. On the eastern end are the Conservatory of Flowers, the De Young Museum, and the California Academy of Sciences. A little farther west are the Japanese Tea Garden and the San Francisco Botanical Garden. All of these are fairly close together, which makes for a great day wandering the pathways from one spot to another (with some interesting people-watching in between!). If you head more to the western end of the park, you'll see the bison park (really!) and the windmills, and end up at the Beach Chalet Brewery & Restaurant, which is a great spot for a bite to eat and a beer -- and on weekends they have live music. From there you can head across the street to Ocean Beach, and maybe grab a bonfire pit for a sundowner.
If you're a foodie, the Ferry Building is always a good stop, esp on Saturdays for the Farmers' Market. Red's Java House is a little farther south along The Embarcadero, and perfect for a burger & beer on the patio when the weather is nice. The Mission District is also a fun (and funky!) option for interesting shopping and dining options. Both can get crowded, but should still be fairly easy to navigate.
Finally, look for Off the Grid: San Francisco down at Fort Mason -- when the weather cooperates, it's a great area to wander around, and end up at the truck extravaganza -- everything you can imagine, plus live music.
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