Manchester to Newquay, Cornwall is 324.5 miles and should take approx 5 hours 54 minutes according to AA route planner.
The driving distance is 57 miles. The time needed to drive is 1 hour and 8 minutes.
About 6 hours
3.5 hours without wee break !
About 4 hours and 54 minutes.
Google Earth calculates the distance as 167 miles - with an estimated driving time of 3 hours 17 minutes.
A lot.
4 and 1/2 to 5 hours
36 days!!
6 and 1/2 to 7 hours
The distance from London, England to Cornwall, England is 269 miles and takes approximately 4 hours and 45 minutes.
If you are asking about the Cornwall in England, then you can't drive from there to Los Angeles, because of the ocean.