This is the photo I mentioned that has great detail and was taken the month of the first event at the track. It is 1 meg vs 26 megs. I will Facebook PM the original (26 meg) if not too large........our last hope would be to e-mail. This gives a lot of detail on surroundings of facility........golf course, lakes for hydro-plane racing, etc.............as well as the public road that ran very close to the track in right of photo.It is different than this one, but this one is pretty good as it shows just how void of foliage the complex was.....just to the right of the pit lane at the top was the garage.....which was state of the art for its time. Just "north" of the pit lane was the grandstand area and just behind the grandstands were the restrooms and concession stands. The golf course can be seen in your photo. The wooden guard rails began at the end of the lake area at bottom of photo and extended to pit entrance. The downhill section is on the left and the uphill section is on the right. Highest point of the circuit is upper left and lowest section is in the lake area mid photo. It was a very sandy area and the drivers complained of the track being slippery due to sand.
Side Note: I grew up two miles from the tracks (8) as they were being constructed.
Thanks for all that you are doing.
One interesting fact about this photo....just left of center of photo you can see where grading had actually been started on the two mile tri-oval. Pit out and turn one can be seen cutting across the road circuit pit lane. After visiting Riverside and seeing 80,000 folks at a road race the developers pulled off grading the tri-oval and built the 3 mile road circuit.