Earlier quoted context omitted.
There are suburban "downtowns"/shopping districts near many BART and Caltrain stops where it's quite possible to commute and do most everyday errands on foot/bike/transit. Possibly even easier than a lot of the southwestern half of SF proper. (Having no access to a car at all - through friends or a willingness to use Lyft/Uber - does make some things harder). The older and higher-density suburbs tend to be better for…
The walkable parts of those cities is vanishingly small, on the order of a few square blocks. The tiny walkable segment is also super-expensive.
Berkeley's walkable area encompasses all of Telegraph Avenue down to Ashby (Berkeley Bowl) (South), all of downtown (West), the perimeter of the UC Berkeley campus and the campus itself, and probably half way down University avenue (further West), the North Berkeley area to the north of downtown Berkeley (Chez Panisse, etc...) (North). If you like walking, you can walk from campus all the way to the Bay. If you like hiking, you can hike up part of the way to the LBL. San Pablo Ave is also walkable but wasn't as ritzy.
The inaccessible directions are NE and E. W was considered ghetto but has gentrified. The only parts harder to walk are up in the hills (pretty much impossible: narrow, windy, steep, no sidewalks) (E) and the hilly parts of North Berkeley (NE).