The first stop on that Saturday will be the City Market. It's been an active marketplace for 150 years.
These days, there is a Saturday Farmer's Market with some incredible photo ops of fruit & veggie stands, livestock, old bldgs and people/product of many ethnic origins.
Bring model releases if you plan to use any of the photos commercially. Bring some color film along if you have it. I'll have some RVP50 in the SLR ready to go.