Travelling back today from Norfolk and the queue on the single lane section leading to Caxton Gibbett was 1 mile plus and we'd missed most of the peak traffic.
There is already a bus service from Cambridge to Bedford, MK and Oxford, it's the X5 with 31 stops, Cambridge to Bedford is 1H20M Bedford to MK station is 55M and MK to Oxford is 1H 20M it's approx hourly.
On this section (East) I'd actually say that Cambridge is the destination rather than MK