I think this place already has enough reviews to give you a very solid idea of what to expect when you visit the CRFM. I am surprised they don't have five stars but I it's possibly because they're not hipster enough, like Atherton Mills or NoDa.
Some of my favorites are the massive flower stand which makes the entire place smell awesomely! This weekend they had two vineyards doing tastings (where are you regional breweries?) and every other stand seemed to be baked goods of some sort.
Expect seasonal products depending on when you go. During this trip the most we saw of were:
local honey
bittermelon
corn
pumpkins
and
squash
I always look forward to all the samples! Go hungry, you'll be full (and carrying more bags of stuff you just bought) by the end of it.