My sister had to drive me, and I couldn't last long at all. It's not too far from my parents'. Unfortunately, I was in the City for my best friend's (from grammar and high school) funeral....
I remember Walnut Creek when it was a quiet little village with walnut trees and a nice plaza! BART used to be fun when it first opened; it was so futuristic and we'd ride around all day. Sadly, CA got way too crowded for me awhile back.
Sorry to hear about your friend - not a happy reason to visit.
I don't remember Walnut Creek from a time when it was a village - I moved here in 1993.