Chard Walker mentioned Camp Cajon in both of his books on Cajon Pass. As well, I recall mention of it on the ( now gone ??? I can't find it ) website Forgotten Highways and Byways of California.
Back in The Day, my dad would haul his drinking buddy, me, a school buddy or two, and our trail motorcycles to Cajon Pass for the weekend. We always camped at the new ( 1939 ) bridge over Cajon Creek at M.P. 63. The 1st trip I can remember was in late 1977, as the new line around Sullivan's Curve was starting construction. We discovered the box culvert under Interstate 15 ( right under the truck scales ) that allowed Crowther Creek to drain into Cajon Creek at the TT East End of Cajon Siding. Riding through the culvert allowed us to safely access Tiffany's Restaurant without riding our non - freeway - legal motorcycles on Interstate 15. The remains of Camp Cajon were still visible then on the East side of the culvert. We would also hike the old Right of Way from Cajon Siding South along Route 66 down to Cozy Dell. Good Times ...