Hi Steve, York would be a great city to go to. From King's Cross Station is a 2 hour trip, trains leave every 30 minutes. York is very rich in history, encircled by a 13th and 14th century city wall its about 2 1/2 miles long, which you can walk on. York Cathedral, which is on of the great cathedrals of the world. The stain glass windows is from the Middle Ages, the Grest East Window is fantastic. There is a street by the name of Shambles, it dates back before Norman Conqest which is fun to see. If you go don't miss Betty's Tea Room, 6-8 St Helen's Square great place for tea and scones. Another area which would be great would be the Cotswolds which you could get to from Paddington Station, train to Moreton-in-Marsh. If going to Cotswolds, I would stay in Bourton-on-the-Water, its beautiful and I really think you and your wife would enjoy it. Lots of small villages around you could visit.