I have even been considering the idea of riding this stretch as some unearthly hour on a summer's Sunday morning to avoid the worst. Providing I left LE at 5am, I would have hopefully reached Lanceston and the shelter of the old A30 before the new A30 turns into a motorway.
Sorry it's my 1st post,i completed john o'groats to lands end 3 weeks ago.
The A30 between Lands end to Penzance is okay, other than that stretch i'd stay off the A30.
Even at 6 am to 7am the A30 was busy.
Another road i found too fast was the A38.
I often cycled very early in the morning during my trip, any time from 1 am to 6 am.Many roads were quiet at that time.
You can go from Penzance to Camborne on quiet back roads [look for B3280 on the map] it goes through Praze an beeble/Leedstown/Goldsithney.It's not a hilly route.