annhig, I agree janisj's suggestions are very good. But tell me about getting from St. Pancras to Paddington. How do you do it? (To the OP, annhig lives in Cornwall.)

Re: open jaw, janis has explained it. Often people spend money and valuable vacation time getting back to their arrival city for a round trip return. When they could have saved their money and had less stress and more time to sight-see if they'd done an open jaws trip.

I almost always do an open jaws routing -- using British Air frequent flyer miles. But sometimes people get such a good deal on their round-trip tickets, they don't want to give it up. Always worth comparing though.

not annhig . . . but St Pancras to Paddington is easy -- depending on time of day and luggage situation, a cab, the tube or a bus all work.

Even though the tube is easy -- w/ luggage getting from Paddington tube station up to the mainline station can be a crowded slog. I'd just take a cab (or a bus if budget is an issue)

The Hammersmith and city line goes directly from ST Pancras to Paddington, and the stairs at the bottom of which you exit the train at Paddington leads onto a bridge which goes straight to the platform for the Penzance train, down to which there is a lift.

but there isn't, so far as i know, a lift up onto the bridge - you have to take the stairs. so JJ is right - it is a bi of a slog. OK if you're just traveling light, not so good with heavy luggage.

The last time I arrived at King's Cross, we waited in the taxi line for more than an hour. So maybe that was then and traffic was bad that day. But still.... Sounds like the tube is the best bet if the OP doesn't have too much heavy luggage and isn't traveling during commute time.

So, after much reflection, we've come up with a whole new plan that includes a side trip to Zurich to visit our exchange student who's just gone home and misses us ;-)
Sadly, we've dropped Cornwall from our plans.
We really want to get to the Scottish Highlands so we'll fly to Edinburgh & drive down to London.
janis - I'm a huge Diana Gabaldon fan & want to visit the Culloden battlefield etc

Day 1 Arrive CDG
Day 2-5 Paris
Day 6 - Fast train to Zurich
Day 7- 8 Zurich
Day 9 - Fly to Edinburgh, pick up car
Day 10- 14 Scotland
Day 15- 17 Lakes District
Day 18 -19 York
Day 20- Drive to Birmingham via Holmfirth ( ancestral home)
Day 21- ?
Day 22- ?
Day 23- Good Friday - Drop car off somewhere ( Cambridge maybe?) & train to London
Day 24-27- London
Day 28- Eurostar to Paris
Day 29- Fly home

Does this look doable? So much to see & so little time to do it! Not sure what the best route from York down would be and I'm worried we've left ourselves really short of time in London

As you're in Holmfirth on day 20, rather than go on to Birmingham (not that much to recommend in Birmingham), drive to Manchester instead. It's only 45/60 minutes from Holmfirth depending on time of day and the city has much to offer in terms of history and buildings, a great choice of hotels and restaurants.

The city centre is easily walkable and you can catch a train to London that arrives in a little over two hours. You can drop your car in Manchester without any problems.

oh dear, how often have I read that people have dropped Cornwall from their itineraries?

but unless people are prepared to fly, [and I don't understand why they won't] it is difficult to fit in, as you've found, Kwaussie. [that wasn't a dig at you, BTW, just a general moan].

the new itinerary looks great. To fill in your extra days you might think about seeing the Peak District - between Manchester and B'ham - or just extend your times in the other places - for example, by the time you've got to the Lakes, you'll only have 2 ½ days there which is nothing like enough.

I hope you have a fantastic time and come back here and tell us about it!

Thanks for the reassurance annhig. It's soooo hard to make decisions from the other side of the world!
Now I really just need to make a decision on where to drop the car. I figure the days between Scotland and London can then be decided closer to our visit & the weather (e.g. I'm guessing if the weather is fine we'll want more days in the Lakes, if it's wet, we'll want less).
Is it worth pushing on to spend the last night in somewhere significant closer to London like Cambridge or the Cotswolds? I feel like if we take the train from Manchester we'll miss (another) good bit of the country.

Cambridge makes no sense w/ the rest of your itinerary. Wrong side of the country . . . Unless you head there from York.

No reason to include B'ham. If you do travel via the Cotswolds, then you might as well drive on to LHR, drop the car there and take public transport into London.

"I feel like if we take the train from Manchester we'll miss (another) good bit of the country."

If you don't have those couple of days in Manchester, you'll miss that too! As you've said above, you can't do it all with two weeks in the UK, so it's always a trade off to visit one place over another. What prompted me to suggest Manchester, (although I'm biased in any case) is that you're leaving York and heading for Holmfirth on day 20. The best place of any size within an hour's further driving, with everything to offer is Manchester.

It may not be as fashionable to visit as the Cotswolds for instance, but they're overrated anyway. I've had a number of emails from people who have visited following recommendations on another site and all have been on a "very glad we went" theme.

Well I'm not in the very-glad-I-went-to-Manchester group. But it was a convenience.

However, there's lot's of interesting countryside and small towns between Holmfirth and London. Sounds like you're less interested in cities on this part of your trip. (Makes sense while you have a car.) You could spend spend a day or two in the scenic Peaks District, between Holmfirth and Manchester, then drop the car in Manchester and train to London. Or drive to the Cotswolds, spend a day or two, then drive to Oxford instead of Cambridge and drop the car. Explore Oxford and take the train to London. There are a lot of possibilities between Holmfirth and London.

No need to decide right now. Book the car for the duration and spend some time researching. You can always change your rental car booking.

Manchester is ok but given that it is not York or Lincoln both of which are smaller and way older it is a funny choice. For me I'd stick to the east of the Penines on the trip south and drop by Cambridge or Oxford if you have time.

Sorry bilbo, not way older. All three places were settled initially between 48 and 80 AD by the Romans.York has the Minster and some narrow streets, Lincoln has a Cathedral and not much else. Granted the bulk of Manchester's visible history is Victorian, but it's too easily dismissed by those who don't know it.

It's a fascinating city with enough to keep most people busy for days on end.

Rubi, I know some of the old bits of Manchester ;-) there is a pub...

I think for advice to a tourist you are being a bit optimistic. But I know where you are coming from. Who can deny the merits of the Library, the museums or China Town?

Lincoln Jail

Oh bilbo, how little you know of one of the most vibrant cities in the UK, with history coming out of its ears! How about:

Library: Central or Rylands?
Town Hall + Bell Tower visit
Peterloo Massacre site
St Anns Square where Bonnie Prince Charlie rode
St Anns Church
Art galleries
Museums
Castlefield Roman site
Manchester Cathedral
St Mary's (The hidden gem)
Imperial War Museum
Old Trafford football ground
National Football Museum
Various magnificent buildings that used to be cotton warehouses, available to visit
Some of the best restaurants in UK

and as Yul Brynner said in the King and I, "etcetera. etcetara."

been, seen ;-) don't disagree but very urbanised