it seems to come down to either which scooter would actually be the best for the trip, or which scooter would look better in the film. To me they would be complete opposites. No doubt a modern big wheeled scooter would be better for the trip, but a vintage (or vintage copy, like the Stella) would make the film a lot more interesting.
2002 Vulcan 750 (now being slowly reassembled) 2013 Royal Enfield B5
2001 XT225, 2009 Genuine Stella
1980 Puch moped