Southwest England...do I go all the way?

You don't say if there are other places en route you want to stop at, or to just concentrate on the South West.

If the latter (and arriving at LGW in the morning) the obvious answer is to take the Eastern Airways flight from LGW to Newquay and start from there.

If arriving later in the day then overnight at LGW for the early morning flight next day to Newquay.

If the flights were not already booked another option would have been Aer Lingus to Exeter (connecting on one ticket at Dublin) and starting the South West from Exeter.

6 hours from Gatwick to Penzance without stopping would be a good day. It has taken us 10 hours. I would consider flying to Newquay and hiring a car there. Or perhaps the Riviera Sleeper from Paddington that arrives in Penzance around 0730.

With 12 days it’s definitely not crazy to go as far as Penzance. You will find tons of things to do in Cornwall so I wouldn’t worry about that. You’ll have a great time.

https://www.visitcornwall.com = the official tourist board website.
https://www.visitdevon.co.uk = the official tourist board website for Devon (the Country which is east fo Devon).

Should you drive to Cornwall on the M3 > A303 route, you will pass Stonehenge. Montacute House is just south of this route near Yeovil. https://www.nationaltrust.org.uk/visit/somerset/montacute-house

I would say you have two main options here, and it would be worth looking at the websites linked to above before you make your decision.

One would be to focus specifically on Cornwall, with an emphasis on the far west. You could, say, overnight in London and then take the train from London Paddington down to Penzance, or take a sleeper train, or fly direct to Newquay, then pick up a car and explore Cornwall. You have plenty of time, but also there’s plenty to see.

The other option is to pick up a car and slowly make your way down, giving some time to equally wonderful Dorset and Devon.

Or a hybrid - train/plane one way and meander back by road - although that would incur a one-way car hire fee.

Both Rough Guide and Lonely Planet do guidebooks for Devon & Cornwall so it’s worth getting a sense of what’s there.

Yes, the Minack Theatre is amazing. I was lucky enough to see an excellent Joni Mitchell tribute show on a summer evening this year, and the band was upstaged by dolphins.

There are some great towns worth a stay of two or three nights. Somewhere like Wareham or Lyme Regis in Dorset. Then maybe Totnes or Dartmouth in Devon would warrant three nights, as there are lots of things to see around there, including both coast and Dartmoor. In Cornwall, somewhere like Padstow, Fowey or Looe would be a good base for the eastern end of the county. And I love Penzance as a bustling friendly town down in the far west. All of these would warrant a three night stay at least.

I went with my daughter and my Dad to stay near Mullion for a week last Easter. We were never stuck for something to do. We went out exploring every day, walking along the beaches and cliffs and stopping for a glass of wine in some of the lovely old Victorian cliff top hotels. The weather was pretty rubbish but we still had a great time.

Places we enjoyed : Porthleven, Cadgwith, Helford, Kynance Cove, Mullion Cove, Poldhu beach.

Thank you to each and every one of you for your comments. I really appreciate the perspectives and recommendations and it helps me move forward with figuring out our plans. I hadn't thought of many of these things, so I'm thankful!

For anyone going down to Cornwall and isn't just interested in the standard tourist sites I highly recommend this U Tube Channel- https://www.youtube.com/@CornishWalkingTrails

They publish a new video at 8am UK Time (3 am Florida Time) every Friday morning.

The problem with the Sleeper train is that you would need two cabins- you can get them as interconnecting cabins which is a plus, but no family cabins. The Riviera Sleeper is a far better train than the Caledonian Sleeper to Scotland (and way cheaper). They use the older Mark 3 sleepers. They always were a great ride but from a recent journey I'm sure they have been fettled up as the journey was super smooth to the point that (even seated) you barely knew you were arriving or leaving a station. Like many other people I can't speak highly enough about the experience.

However if you have arrived in the early morning at Gatwick that is a long time to wait. There is a broadly hourly train from Paddington which does the journey in between 4 hrs 55 minutes and 5 hrs 20 minutes. Last one at 1903.
All trains stop at Reading, so you don't have to go to Paddington to catch the train. Every 30 minutes there is a direct train from Gatwick to Reading which takes 1 hour 27 minutes- no faster than via London but much easier.

So if you take the train to Penzance on arrival day there are several hotels close to the Rail Station- but the Premier Inn is literally over the road. Then next morning back over the road and the rental car lot is across the road from the station entrance.

If you opted for the train get a family and friends railcard for £35 (£30 before March) to get 30% off your fares, and 60% off the children's fares.
Travelling today on walk up fares you would buy this as separate tickets Gatwick to Reading and Reading to Penzance £40.20 and £117.30 (total of £157.50). The railcard has saved you £119.

If you ended up on the 1303 or 1903 from Paddington on a weekday (1329 or 1929 from Reading) there is also Silver Service Pullman Dining (even for 2nd class passengers subject to space).

Looking at 8 January as an example the sleeper fare for the whole family with inter connecting cabins would be £429.90 with railcard, in two inter connecting cabins.

Sorry, but one last voice saying, “Go west, young family!”

Cornwall is magic. Penzance, St. Ives, St. Just, Mousehole… magic! And you’ll be able to say you were at Land’s End - such a romantic and glorious sight.

Sounds like you’re considering it. Please do - and have a (magical) blast!