Good viewing area up the road past the main gate. There are instructions online to find it:
“There are two viewing areas for launches at Vandenberg Air Force Base (VAFB).
* Weather Station: The public viewing site for Vandenberg launches is off of Corral Road near Vandenberg's main gate. To access the area, take Highway 1 to the Santa Maria Gate and proceed on Lompoc Casmalia Road. At the barriers, turn right onto Corral Road and bear left to the top. The launch countdown net and port-o-lets are set up near the bleachers.”
“There are two viewing areas for launches at Vandenberg Air Force Base (VAFB). * Weather Station: The public viewing site for Vandenberg launches is off of Corral Road near Vandenberg's main gate. To access the area, take Highway 1 to the Santa Maria Gate and proceed on Lompoc Casmalia Road. At the barriers, turn right onto Corral Road and bear left to the top. The launch countdown net and port-o-lets are set up near the bleachers.”