York my favorite city, love the place, visit Dungeons then walk down the road to the river and take some refreshment in the Kings Arms (probably the best known pub in york, due to it regularly flooding when the River Ouse gets up) if your lucky can get a seat by the open fire looking out on the river, also does pub food. Agree the Castle museum is worth a look. We did one of the ghost walks started outside the pub, after a few hours in there you will believe anything, but the walk was entertaining.
Plenty of reference to railways on here, many years ago the end of the station platform was where i would have been, watching the mighty Deltics coming and going, was hooked from my first visit with our school railway club around 1977, subsequent visits lured me to pubs in the city as i got older, once girl friends came along the trains spotting went out the back door, but still kept visiting with wife and kids(we spent our honey moon in York) never get fed up of the place.