I know an ex BOAC 707 Captain, now aged 90 and put the question to him. He has just checked one of his many logbooks. Incidentally he achieved a speed record in the early 1960s flying LAX-LHR in 9hrs 15 minutes, (airborne not chock to chock). He says it might have been SF0-LHR though.
Back to the question. He operated BA 591 LHR-LAX on Jun 3rd 1962 in B707 G-APFG. It went via JFK which is where he got off. Strangely his next sector was from JFK-Kingston. He reckons he must have been supernumary on the BA591 as he has the Captain's name down as Buxton and not himself.
From my logbooks (Times GMT Not UTC !! )....
30th July 1962 G-APFM BA 581/643 London 15.15 - New York 23.30 = 8:15.
31st July 1962 G-APFM BA 581/643 New York 13.22 - San Francisco 19.27 = 6.05
10th August 1963 G-APFG BA JBH/7141 London 10.38 - Montreal 17.48 = 7.10
11th August 1963 G-APFL BA 591/307 Montreal 20.00 - Los Angeles 01.30 = 5.30
I have absolutely no recollection of these flights, but my logbooks suggest that the SFO service had a nightstop in New York, ( same aircraft, same service number ) and the LAX service continued same day through Montreal. The August flight from London appears to have been a charter for some reason, i.e. not a normal service number. No idea. Make of it what you will. By the way, I recall Captain Buxton, a quick flick through my logbook shows that I flew with him on 23rd August, 1966 London / Bermuda / Miami and return.
I do recall that on one of my early flights across the USA, New York to West Coast, all of us were "new" to the route, and in New York the Captain had bought a road map of the USA, and ticked off various items, cities, of interest as we flew along. A passenger visiting the forward toilet looked through the then open Flight Deck door, and said " Geez, don't you guys know the way ? "