In reminiscing about Zeli in La Canada, in the first episode, Stef brought up it's cozy setting with a private area with a curtain. Many scripts were written here, as mentioned, including her participation in the annual NaNoWriMo (a writing marathon for novice Novelists). But the venue was much smaller than one might imagine, and the private room only allowed a table for four. 

Not much information was found online, but at least we have evidence of it's existence through found images on Yelp.

Their prior location was: 639 Foothill Blvd, La Canada Flintridge, CA, US, 91011