I live in Hayle and ride that route as part of my ride every sunday, if you click here you can view my ride in google maps,,
http://maps.google.com/?t=p&z=15&ll...gps/host/3b059f70-c3ee-44f9-87c2-86c2c95fad52
If you stick to the cycle network routes which are clearly sign posted, you should be okay.
Hardly any traffic today, and the majority of traffic do give you a wide berth around here.
St Ives through Zennor to St Just can be quite challenging, more so with a strong on shore SW breeze, and a few bumps from Lands End via St Buryan to Mousehole.
The built up areas of Mousehole and St Ives can be streaming with dopey emmetts, all of whom tend to leave their brains at home and just don't take any notice of cars etc as they walk 6 abreast down the roads!!
As already said, it will be hard going for small children as there are some bloody steep bumps to deal with which does get the old ticker pumping.
Enjoy the ride,,,,