Short sections of Highway 1 have been single lane for years. That's no problem.
Yeah that section of Big Sur gets very heavily traffic especially during summer months, it's already bumper to bumper during summer weekends without single lane restrictions. And if they plan to do extensive roadwork managing traffic becomes a huge headache, so suspecting there will be extended shutdowns of the read which causes headaches for getting catering and employees on site. I don't want to paint too bleak a picture but probably prudent to have backup options for a few months.