I know what you're thinking: how can I take my RV to and through San Francisco? It has hills and narrow streets and is RV unfriendly. Well, I travel there quite frequently, know where to park and where all the free stuff is. Since I was setting up my calendar for next year, I thought I would share.
First, there are two ways to enter San Francisco with your RV from the north and east: over the Golden Gate Bridge via 101 or the Bay Bridge via 80. If you go over the Golden Gate, the basic fare for a two-axle vehicle is $6 and each axle is charged another fee. My suggestion is to leave the city by that bridge and enjoy the view going across for free.
After you cross the bridge, take the 19th Street/Highway 1 exit and travel south to Geary Blvd. Turn right on Geary and drive until you see the ocean. Stay on the big sweeping curve onto the Great Highway past the Cliff House and turn right into the large parking lot on Ocean Beach. That is Golden Gate National Recreational Area property and part of the National Parks Service. It's safe to park there and falls under the jurisdiction of the park rangers so you won't have to worry about a parking ticket.
Walk to the intersection of Balboa and the Great Highway, turn right or south on La Playa, and continue walking one block to the bus stop across from the Muni turnaround. There is a Safeway store with a Wells Fargo Bank inside. Take the 38 Geary, give the driver $1.50 and take the transfer. It will usually be good for at least three hours. The 38 Geary will take you across the city and the route ends south of Market Street where you can catch just about any bus or streetcar to your destination.
If you enter by the Bay Bridge, the basic fare is $4 with fees for each additional axle. Take the Ninth Street exit, turn right on Ninth, following it to the left onto Hayes Street, and turn right onto Van Ness Avenue. Stay on Van Ness until you reach Geary Blvd. and turn left. Follow the directions above to reach Ocean Beach.
If you're traveling north on 101, take the Ninth Street exit and follow the instructions above.
All streets have Muni buses traveling on them so you can safely travel on them with your RV.
If you want to leave your RV outside the city and are traveling south on 101, take the Sir Francis Drake exit, turn right and go past the Larkspur Ferry parking lot. There is no RV parking in the lot but you can park safely across the street from the stoplight facing west on SFD. I make a U-turn at the light but my RV is only 27 feet. Once you're parked, go to the ferry terminal and purchase a round-trip ticket which will be around $15. Take the ferry to the San Francisco Ferry Terminal and when you exit, take a free Muni bus ticket for your round-trip back to the ferry. When you leave the building, walk two blocks to Market Street and you can take any bus or streetcar from there. http://www.goldengateferry.org
Now what can you do in San Francisco for free?
First Saturday of every month: from 8 PM to midnight, singing sea chanteys on the Balclutha, a three-masted sailing ship at the Hyde Street Pier, the world's only floating national park. Bring a mug for hot cider or cocoa (donation if you wish). The Maritime Museum across the street from the pier is free every day. http://www.nps.gov/safr/
First Sunday of every month: free day at the Asian Art Museum. http://www.asianart.org
Beginning around the first weekend in May until the last weekend in September, weekly Sunday concerts from 1-3 PM by the Golden Gate Park Band in Golden Gate Park. Bring a blanket or chair and a picnic lunch. http://www.golden-gate-park.com
Beginning the second week of June through the second week of August, weekly Sunday concerts from 1-3 PM in Stern Grove. Bring a blanket or chair and a picnic lunch. http://www.sterngrove.org
First Tuesday of every month: free day at the DeYoung Museum, Palace of the Legion of Honor and Museum of Modern Art. (MOMA) http://www.famsf.org or http://www.sfmoma.org
First Wednesday of every month: free day at the San Francisco Zoo, Exploratorium and California Academy of Sciences. http://www.sfzoo.org or http://www.exploratorium.edu or http://www.calacademy.org
That should get you started on your very economical visit to San Francisco.