The B660 is a fab route.
Quiet short route with some nice corners 1 after the other.
Really good for the area.
Very nice twisty roads and fast sweeping bends, highly recommend.
East Anglia is notoriously flat and lacks lots of bendy fun roads. This is a great shortish loop with some interesting sweeping corners, quiet roads when you're out of town and pretty countryside. Some potholes at the moment (driven in April 2018).
It's no alpine pass but is the best of what we've found so far within an hour from Cambridge.
Best section of this ride is Linton to Barkway.