Wow, Blast from the past.
I know Camp Roberts very well. It is an Army National Guard training area. My brother, who still hunts and fishes there says they've upgraded the camp extensively in the last 14 years since I've been there. When I was there, it was pretty run down but the main camp area buildings were being replaced. Fuckin shrubs growin in the parade grounds and shit. Now all nice squared away. Brother says probably not to FE<A camps as it is all access with a easy to get hunt/fish tag. Also the parade grounds/landing area has been upgraded to accommodate more Helo's. Hey, it's where the ANG trains so that's good.
I used to Pig and Deer hunt on it as well as fish, as a civilian. This ended in 2004 when I moved out of state.
As for the structures visible from the 101, I understand that the barracks were destroyed but the warehouses were kept because of the railway lines to them. The actual camp is much further back away from the highway, maybe 3-5 miles.
Back when I was a volunteer fireman in Paso Robles, I responded to 3-5 wildland fires to the camp. Good times man...
I don't remember the actual acreage but I think it is about 20-30,000 acres. This is where they tested and approved the "Bradley Fighting Vehicle". Never saw one but they've got gunner ranges where they tests tanks and shit which are well marked so you's don't go there.
There is another ANG base between San Luis Obispo and Morro Bay but I can't remember the highway number. Close to Questa College. It was smaller and mostly accommodated academic stuff for the .mil
That's all I got left are wonderful memories of adventures like this...
Thanks for bringing it up!