Getting to York from Heathrow

4 hours is fine. You may well have time to a look at St Pancras across the road which is magnificent.

The timings seem reasonable to me, barring any major delays to your flight or very unpredictable delays (I once had to wait an hour at baggage claim when there was some issue getting the bags off the plane). Passport control is pretty quick these days if you can use the machines- these are open to people with US passports, EU, and a few others, and you have to be over a certain age (I think 12?)- so if you're travelling with a small child you can't use them. As you probably know Heathrow is huge so a lot of your time will just be spent exiting the airport, even if you don't really have to queue.

I personally would take the Elizabeth Line to Farringdon and then transfer to the tube and go one stop to King's Cross. It's a much nicer journey, particularly if you have luggage, and only a little more expensive.

If you need something to do at Kings Cross, one of my favourite pubs in the area is The Parcel Yard which is inside the station, up the steps at the end. You can watch the trains arriving and departing. The Booking Office in St Pancras next door is also a very nice place to wait. It's in the hotel but open to non guests. If you have lots of time to wait you're also right next to Coal Drops Yard which has restaurants and shops, though if you have a lot of bags you may not want to be walking around. Good luck with everything!

"you have to be over a certain age (I think 12?)"

Currently 10. As of 8th July it will be lowered to 8 years old.

Two days ago (so a Monday, not a Friday) I was on the 1633 and was amazed it was a nearly empty train. There were 3 people in my (admittedly 1st class) train car.

And a week ago I was on the 1433 and that was less than half full. A pattern of the xx33 trains developing there- they are basically slightly slower (by 10 to 15 minutes) relief trains, running 3 minutes behind a fast non stop. The

So the 1533 could be a good train to book on.

Make sure you reserve seats at time of booking. I know there’s every chance that travelling mid afternoon will mean the train won’t be that busy and you may have a choice of seats, but I would always reserve my seat in advance, because you really never can tell.