When Courtney leaves the wedding to look for Christina, the wedding march has begun as she leaves the pew and starts up the aisle. The next shot is of her outside the church and on the lawn, but the music has played continuously without enough time for her to have walked that far.
When Vera is displaying mannequins in front of her store a car
drives by hitting and dismembering the one in the blue/green dress, but when Roger and Peter are bringing the mannequins they only bring in the red one which only lost one leg.
On their way home from a nightclub towards the end of the movie, there is a close-up of the three girls, shoulder to shoulder in the back seat of a taxi, presumably so they all fit into the shot. Next is a wide exterior shot of the taxi and the girls are spread out across the back seat, with plenty of space between them.
When Christina and Courtney are in the Car on their way to the wedding, they look at their map and mention taking Interstate 95 and 40. Those interstates are located in the east coast. Interstates near San Francisco are 101, 880, 80 and 280.
When Peter turns the pages in Vera's mailing list guest book and lands on "Christina Walters loves Peter," the zip code written is "94587" which is the zip code of Union City, California, a smaller city in the east bay area.
Somerset is east of Sacramento. They would need to take 80 and 50, not the highways they were talking about. Not to mention, the area code there would be 530, not 510 like on the bench billboard (510 is for the East Bay).