About 3 hours and 31 minutes.
About 6 hours
I depends on where abouts you are in Cornwall. From truro, it takes around 1 hour 30 mins by car.
It depends whereabouts in Cornwall you mean. As an example - Google Earth calculates the driving time from Bournemouth to Penzance as 3 hours 49 minutes for a journey of 195 miles.
Cornwall is a large county. To be specific this answer is for time and distance between Truro and Peterborough . The AA online route planner gives a distance of 331.8 miles, and a driving time of 5 hours52 minutes. Link to the route planner is below
Google Earth calculates the distance as 167 miles - with an estimated driving time of 3 hours 17 minutes.
It depends where in Cornwall you want to travel to. Based on St Ives it would be between 6-7 hours with 2 changes. For Truro station you would be looking at a journey 5-6 hours with 1 suggested change en route.
From Paddington Station in West London to Truro (the administrative centre of Cornwall) the fastest trains take about 4 hours and 20 minutes to cover the 400 km (249 mile) journey. A car journey from West London to Truro would take about 4 hours and 30 minutes using the A4, M4, M25, M3, A303, A30, M5, A30, and A39 roads (420 km; 261 miles).
The travel time between Brighton and Bournemouth by car is approximately 1.5 to 2 hours depending on traffic conditions. By train, the journey can take around 1.5 to 2 hours as well, with direct services available.
In the twinkling of an eye. Less than a second. If you in the right part of England. England is a country, and Cornwall is a county in England. So if you are in Cornwall, then you are also in England.
It takes about 3 hours by road to get from Heathrow Airport to Bournemouth.
1278mi/ 2057km
about 2 hours!