We are heading up Highway 4 early tomorrow, 8/9/19, and plan to get to Lake Alpine Campground by 9:00 A.M. How likely is it that we will get a site?

Generally... Not likely! However, there is a few campsites that are based on First-Come-First-Serve. There a few of these on Alpine Campground right before you reach the lake on your right.. If I remember correctly, sites 19, 20, 21, 22 are FCFS. Good luck!

Go on reserve america and you can reserve

9 am is likely, the host is very helpful