I had a mission in going to McLaren Park.  I wanted to see whether the new Shelley Promenade would be accessible for people with disabilities.  When I got off the #29 bus, my gps lead me through a dog park and down muddy hills.  But it was an error.  The bus stop on Shelley and Marston is right on it!  Also, at the other end of the 1/2 mile stretch, there's a parking lot!

https://www.sfchronicle.com/sf/article/shelley-drive-mclaren-park-18459839.php