I agree on York; It is a very busy town and parking can be a nightmare, but what it has to offer, from the Cathedral down is fantastic. Great shops, many very unusual, plus a very good theatre. Loads of good restaurants and snack bars, not to mention some very good and interesting pubs in town and along the river. History is everywhere from the wall around the city to the various gates by which to enter it.
We too the time to walk along the top of the city wall which, more or less surrounds the city. Also some great architecture if that's your bag....
The racecourse is nearby as is the river.............We went to the city for a week, but spent some of them in the surrounding countryside which is also beautiful.
Well worth a visit, but park your car and walk everywhere........................