Transportation from Heathrow to York in June.

Try googling "Heathrow to York" or rome2rio.com

You can take the Piccadilly Line underground straight through from Heathrow to Kings Cross, and then get a train to York from there. The fare will be much cheaper if you book in advance with www.eastcoast.co.uk, but if you miss your train you will need to get a new full-price fare.

There aren't any direct bus services from Heathrow Airport to York, and over that distance a train will be faster than bus with changes.

Have you considered stopping in London for a few days, then on to York? If you do, it will make for a less harried outbound trip, and the train ride to York can be very pleasant. York is a wonderful city. Also, it would give you some time to consider how best to spend your time when you return to London for a few days before heading home.

Or, consider consider this: DC to London; spend the week; to York by train; fly home out of Manchester. Depending on your airline, you may have a connection at LHR, anyway. That saves you some time by not backtracking through London.

No matter what you do, you will wish you had more time in York, and London. Both are fabulous.

Thank you for your guidance. We thought having a few nights in York might help us get over jet lag even though the travel day itself would be stressful. We would spend a week in London and then take the train to Paris where we would spend 3 to 4 nights and fly home from there.

Thank you for the site for making train reservations. Are return trains open ended or is it cheaper to make a reservation for a specific time and date.

Thanks again for all the comments and suggestions. It is wonderful to be able to tap into the wealth of experience out there. Much appreciated.

You're absolutely right to travel on your first day arriving into the UK. I've done it myself - arrived at Heathrow in the morning and then caught a 3:00 ish train on to somewhere in the afternoon. It's a great way of using the first day and being ready to go when you hit day 2. York is fabulous; there are often free walks offered by local guides that take you all over. Make sure to walk on the walls, see the Richard the third museum and also the Castle Museum. It's not a museum about castles, but rather about domestic life. If you have strong legs, climb up to the top of York Minster, and for refreshments, have a fabulous meal at Betty's tea rooms. :)

Always consider the option of flying into one city and out of another. Even if it isn't cheaper, it saves travel time within the actual time abroad. Of course, if you want to sight see along the way that makes sense too. Unless you are planning to sight see along the way, it seems to me like it would save you a lot of time to fly into Manchester and out of London or vice versa.

As Philip said, booking train tickets in advance can get you a cheap discount fare (as low as £13.00). Last minute fares for long distance high-speed trains are expensive. Book ASAP on the East Coast site (usually about 12 weeks in advance). The cheapest seats sell out quickly.

To make sure you don't miss your train and have to eat the price of your tickets, allow a minimum of four hours between your scheduled arrival at Heathrow and your scheduled departure from Kings Cross. (Five would be safer.)