You will want to go at least as far south as Bixby Bridge, which is the most iconic bridge (the one you see in movies/commercials) on PCH.

The next few scenic outlooks on the Big Sur Coast between Bixby Bridge and Little Sur Bridge are worth pulling over.

After that, the road heads inland to Big Sur (town) which is less scenic.

Pfeiffer Fall trails is a nice short hike which ends at the namesake fall. It's probably a good spot to turn around if you need to stick with a schedule.

The next place that you can turn around is McWay Beach. There is a parking lot for McWay Fall trails so easy to turn around.

If you still want to keep going, you should just go all the way to Lime Creek Bridge which is where the road is closed.