Train Wreck - S1-E20
Revealing mistake: Shari from ISP radios Doug about the rush order pickup at 1202 Stratford, so Doug pulls over and soon Carrie pulls him to the back of the truck. Cut to exterior shot of the truck, and the street sign reads "Lafayette, Culver City" which reveals the California location. The truck is parked on Culver Blvd, corner of Lafayette, in front of the well known Washington Building (awnings are now black), which is located a few blocks up from Sony Pictures Studios where King of Queens was filmed. (00:21:35)
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.