London to Paris or Chartres

London to Paris is easy via Eurostar; tickets are cheapest when purchased in advance. The trip itself is only 2 hours and 20 minutes. You have to check in one hour before departure, but the good thing is that you go through both British exit passport control and French entry passport control in London — so when you arrive in Paris, you just step off the train and go on your way.

Stay a day or two in Paris, then Paris to Chartres is an easy train ride on a local train (no advantage to advance purchase) from Gare de Montparnasse.

Here's the guidance about going from London to Paris via Eurostar from the always helpful and useful Man in Seat 61.

https://www.seat61.com/trains-and-routes/london-to-paris-by-eurostar.htm

Thank you, that looks like the cat's meow to get to Paris. Now I'm going to have to decide to rely on trains or drive from there to the south of France. It looks like car rental now will run 25 to 40 dollars not including gas.

Well, remember that gas is currently the equivalent of something like 7 or 8 dollars a gallon here.

To run a simulation of the costs for driving between two points in France, go to ViaMichelin. You can put in a beginning point and end point, choose the kind of car even (I.e. from small sardine tin to big SUV), and it will calculate driving time, fuel costs, and even tell you how much France's famous toll roads will cost you.

A good ballpark figure for driving costs is that tolls on highways cost 0.15€/mile (on average), and gas for the rental car will cost 0.15-0.20€/mile these days. So 0.30-0.35€/mile total: it adds up, especially on the almost 500-mile drive from the Loire to Provence!

The further out you buy your Eurostar tickets the cheaper they are.

Thanks to all for the input. I'll probably use a combination of train and cars, perhaps tour Paris then train to Lyon to tour Provence, Dordogne with both train and car.

That seems like a good plan. France has excellent train service but it tends to focus on Paris as a hub. Plus driving in and near Paris is no fun at all. Fly to London, get to St. Pancras for the Eurostar (having bought well ahead with a good time cushion in case of flight or entry delays), spend whatever time you choose in Paris, take a train to Lyon (for a clockwise driving loop) or Chartres (for counterclockwise), pick up the car there and use it for the rest of your travel until Chartres or Lyon, as the case may be.

If you can handle the left-side UK driving you'll have no trouble driving in France. GPS and a map would go well together.

Here is a different view, based on watching threads here with people trying to transit thru London to other locations over the last few months.

In the time of Covid, which we will likely still be in next year, I'd recommend if your goal is to visit France that you fly directly in to France. The fewer stops on the way, the better. I do understand the money side of it BUT I think you have to look at more than just that. Who knows what the requirements will be for US residents to enter UK (and to go from Heathrow to Eurostar you would officially ''enter" UK) and what requirements there will be for someone who's been in UK to enter France. You may be adding layers of Covid-related bureaucracy.

Prior to Covid, I'd say go for it. Now, I'd encourage you to look at the big picture with the possibility of Covid impacts.

Also prior to Covid there were nice flights on Delta from SLC to CDG (as well as Amsterdam and London). Hopefully those will be back full force by next year.