There is a mainline from London Paddington to Penzance (8 miles/ 13km from Sennen) with connections at Reading, Bristol and Exeter. Timetables are available on-line from:
from the M5 take the A30 (mainly dual carriageway) all the way to Sunny Corner Lane!
The main roads are mostly excellent but can be very busy in the high summer.
Several budget airlines now fly to Newquay from Stanstead, Gatwick, Glasgow, Birmingham, etc.
More information is available from:
Kate & Craig - Doncaster (Feb 2012);
"One word - WOW. What a way to wake up!"