Yes there is a lovely route by Stourbridge common. It does take ten minutes longer than the A14. I vary, myself, sometimes using the A14, sometimes the pretty route. There is risk in everything, and if you ride down the hard shoulder of the A14 you need to be aware of the gottyas ... tyres coming off lorries, people in laybys opening their doors, lorries swaying over to the left, lorries carrying houses, deep set drains, detritus on the hard shoulder ... I spend most of my time on the A14 checking my mirror. On top of this many concrete brained motorists think that it is illegal to ride on the A14, so will honk at you and call you a twat.
We really need a good east west cycle route that crosses the Cam near Fen Ditton and provides a path through to the science park. Apparently nearly 25% of Cambridge commuters are cyclists so it might not be such a big ask. I shall not, however, hold my breath!