Hi -
If you are hiring a car for York, make sure your hotel/lodging has car parking. Parking in York is a nightmare - public car parks are eye wateringly expensive and on street parking is neglible at best. Driving in York is not fun either - sadly, mediaeval types never factored in the rise of the internal combustion engine! That being said, York is eminently walkable and has plenty to occupy the visitor for several days. The Minster of course takes top billing, but there are interesting buildings and ruins throughout the city and several interesting Museums - we visited the excellent Railway Museum just last weekend and were fascinated!
Harrogate and Knaresborough are close together and only a shortish drive from York. Think of Harrogate as a little like a northern Bath, it is after all a former spa town, although those don’t date back to Roman times. Knaresborough has a castle and the River Nidd between castle and town. There’s also the legend of Mother Shipton and her prophesies (although it turns out the majority were written long after her passing).
Also in the area is Ripon, which is a small city with a cathedral, much bigger than the city ought to have, which is celebrating the 1350th anniversary of its founding this year. Nearby is the UNESCO World Heritage site of Fountains Abbey and the Studley Royal water gardens, which can occupy a full day if you can stroll the extensive grounds. (National Trust and unusually, English Heritage too).
If you are a fan of the recent remake of ‘All Creatures Great and Small’ then many of its shooting locations are in the Yorkshire Dales, which are fairly close at hand if you have a car. You can always DM me for further details of these if you want, but my guess is you’ll have your hands more than full with your three chosen towns in the time you have available.
Hope you have a great trip!
Ian