My first TATL [in July, 1963] was in a DC-6 [actually a USAF C-118]. We routed via refuelling stops:

Rhein-Main 3:10 Prestwick
Prestwick 9:45 Harmon AFB [Newfoundland]
Harmon 4:25 Idlewild [later JFK]

A total of 17 tedious hours in the air, with the added inconvenience of the in-flight meals being accidentally locked in the hold and inaccessible for the 9:45 TATL sector!