They basically close the road in for cars once the car park at Dove Lake is full, if you are getting there before sunrise you shouldn't have any problems, I think there are maybe about 30 car parks? We drove there and arrived about 45 mins before sunrise and there was only one other car there. You will need to have your parks pass before you go there as obviously the office won't be open but the road in has a boom gate which opens automatically once you pull up to it (unless of course they have closed the park for some reason).