Many thanks to sidestand for sharing a video of his ride through Angeles Crest on youtube. He saw Keanu who can be seen beginning at the 7:20 mark. Keanu’s clothes and appearance are consistent with another photo that was taken on November 25 and posted on instagram. Caps are below.
Update: Thanks to RT for the link to this video. Dex also posted a video on December 8 on youtube from this same day. He points out Keanu’s bike in his clip. Dex is the guy in the instagram photo linked to above and he ran into sidetrack at Newcomb’s Ranch. These clips are definitely from November 25.