Hello! Let me say this:
If you are really interested in public spaces and streets, I'd highly recommend the following:
San Francisco:
- Mission Murals. You need a guide to find them, but if you wanna do it on your own, do it during the day on the following streets in the Mission District: Clarion Alley, 18th Street, 19th Street, Balmy Alley, and 24th Street. Of particular interest would be the Women's Building MaestraPeace Mural at 3543 18th Street which houses the Women's Center.
- Bernal Heights. This charming, working class neighborhood is a bit out of the way from the Mission District. But, walk up the huge hill in this district (accessible from either the 67-Bernal Heights or 24-Divisadero bus with Muni), and you will be rewarded with top-notch views of the City sans the tourists. From there, you can decide which parts of the city you want to explore further, from Haight-Ashbury (for a mix of the Summer of Love feel and Victorian homes) to North of the Panhandle to even Japantown and the Fillmore.
- Moraga Street Steps. Located between 15th and 16th Avenues, not only you can see sweeping views of the Sunset District, but you also get to see a unique artpiece from the bottom up. Once you get to the top, you can continue further to Grandview Park, in which locals bill it as one of the best views of the city. Afterwards, you can go towards Lawton St & 16th Avenue and descend on the Hidden Garden Steps, which affords views of nearby Golden Gate Park and the Golden Gate Bridge. Access these areas using Muni bus lines 28-19th Avenue, 66-Quintara, and Muni Metro N-Judah.
East Bay:
- Morcom Ampitheater of Roses. Located in Oakland next to AC Transit Route 12, you get to see hundreds of flower cultivars while affording a lovely view of the Bay from a distance.
- UC Berkeley. A premier center of education, not only you see a variety of architectural styles that house various academic and sporting disciplines, but also a great place to stroll and discover the quirks and oddities found near this university (e.g. Gourmet Ghetto). Accessible via BART to Downtown Berkeley or AC Transit Route F from San Francisco, as well as AC Transit Routes 6, 7, 18, 36, 51B, 52, 65, 67, 79, and 88.
- Lake Merritt, Oakland. Located close to Downtown, Lake Merritt affords excellent views of Downtown from the east side of the lake (from the Church of Christ the Redeemer to the north down to the Alameda County Courthouse to the south), plus great views of Lakeshore Avenue from the west (Downtown) side. Many locals can be found around the circuit of the lake, engaging in many activities from boating to painting to jogging. Access this from Lake Merritt BART station or a short walk from either 12th Street BART or 19th Street BART.
I can provide even more information by sending me a PM and letting me know what else you'd like to see. I live in Marin County, immediately north of San Francisco, so I can be of service to you.
And oh, speaking of which, you can go to any of these county fairs as the 4th of July is approaching:
- Alameda County Fair in Pleasanton (Dublin/Pleasanton BART to Wheels Route 52)
- Marin County Fair in San Rafael (Golden Gate Transit Routes 30, 70 or 101 to San Rafael Transit Center, then Marin Transit Routes 35 or 49 to the Fairgrounds)