I did this alleged cycle route in the Summer. Some very dodgy stretches, with channels and potholes where the surface has been washed away. Loose gravel, at least one big sudden drop which could have been deadly if I hadn't been paying attention. I wrote to Scarborough council about the condition of the route, apparently there is a proposal to repair and upgrade it but a local has objected. There are a few houses along the route, maybe he lives there and objects to the horror of cyclists going past his house.
One the other hand if you don't mind a bit of a challenge, fantastic views in places over the coast and out to sea; and a nice cafe at Ravenscar.