Is Chester or Conwy a better overnight stay if you'll be in the area for a couple of nights? We'll head to Scotland afterwards.
I haven't been to Conwy but my sister has and we both were in Chester this past November. Chester was the favorite town of the UK outside of London for both of us. Just an FYI. Loved this town. Lots of things to do for a day. We stayed above a bar/brewery. We are the sort that likes this. I imagine most here aren't so ask for reccos if you decide on Chester!
We visited Chester for a day, and then spent several nights in Conwy as a base for north Wales. They're very different places.
Chester's much larger, with a lot more to do in the city itself. We liked the cathedral, the walls, the Roman museum, and the streets full of half-timbered buildings. Its location will give you a slight head start when you leave for Scotland.
Conwy is dominated by its medieval castle, with most of the town inside its walls. (Chester has spread well beyond its walls.) It also has a very good restored Elizabethan house, Plas Mawr.
I'd say Chester and Conwy are each worth a full day, or most of a day, to see. Which interests you more?
Be sure to see both. Consider staying for 2 nights in Chester and going to Conway as a day trip by train as it is only 52 minutes away and costs about £20 return. (Be sure to inform the guard that you wish to get off at Conwy).
www.visitchester.com
http://www.visitconwytown.co.uk
www.nationalrail.co.uk
If you are going to Conwy, you are very close to Betws-y-coed which is a charming place on a cascading river and a great place to stay overnight. Also, you are only 24 miles from Beaumaris Castle. If you are planning to visit more Welsh castles, they have a pass. If I were you I would spend more time in Wales before rushing off to Scotland. I promise that you wouldn't regret it. This works better if you are driving.
We spent three nights in Conwy two years ago on our whirlwind UK trip. Conwy was our favorite place! It's a charming fairy-tale like walled town with a magnificent castle. You can walk the walls easily. We walked to Llandudno (wonderful North Wales seaside resort) from Conwy and had a wonderful day at their boardwalk and beach! We didn't have a car so we missed some sights that we would have liked to see. However, now we know we want to spend more time in Wales on our next UK visit. We only changed trains in Chester but from the previous posts it sounds lovely. I would spend a night there before heading to Scotland. Enjoy your trip!