Google's route-finding algorithm is odd. It says the quickest way from Elgin to Cambridge
is M6 to A14, but the quickest route from Elgin to Norwich
is A1 to A14 (right past the top of Cambridge).
Though the two routes are so close by their weightings, so I guess that they've simplified their route finding algorithms in ways that give these odd results. They reckon Elgin->Cambridge->Norwich (via M6) is 11h20m + 1h30m = 12h50m, and Elgin->Norwich (via A1) is 12h55m. Experience suggests they're being optimistic about the A1.