The last verified contact by FJ was the 22:19 July 21 video sent to friends/family, in motion, northbound on N. Adobe Rd, -1.2 miles (2 km)
N of Highway 62.
Ostensibly on the way to the marine base to purchase fuel? The fuel pumps, at the northern edge of the sprawling base, were still nearly 9 miles (14 km) away. The commissary closed for three hours.
Interestingly, fuel seems to be one of few products on base not exempt from taxes.

Gas taxes in CA are 78 cents a gallon, highest in nation. According to gasbuddy.com prices at the base pump do appear to average 15-20 cents cheaper than in town.
Would JRF make a 20-mile detour (recalling my younger self making 20-mile detours to avoid 50c tolls when gas was 70c/gall but JRF is no kid), late at night, to save a coupla bucks? What was he really up to that night?
Now the weather report. 100 deg F (37.8 C) in Borrego yesterday, prolly last triple digit with six month high-season (Nov-April) approaching. That two-month stretch mid-July-to-mid-September, when JRF disappeared until recovered, punctuated with a hurricane in the middle, dropping a years worth of rain in two days, was brutal.
(Finally the traffic report and a fun fact: the aforementioned last contact 22:19 7/21 video appears to capture traffic exiting southbound from Smith’s Ranch Drive-In Theater, 2 km north of vid, a uniquely-American experience and one of the last (actually ~300) remaining venues.
Believe the latest Indiana Jones flick in the middle of a three-night run was being shown that Friday evening. Bring the lawn chairs, the desert comes alive at night. Showtime 19:30, runtime 2:34. JoBob sez check it out. I know, tmi).
ETA: “What was he really up to that night?”