What is your preference for a "base" in Northern Wales? I'll be tromping around the countryside by foot, bus, or rail if the weather holds - and/or- touring the sites, especially if the November rains are out in full force.
For bus connections, I liked Bangor... not much there, but easy bus trips to Conwy, Caernarfon, Beaumaris, and Llanberis.
We enjoyed Betws-y-coed the time we were there. Lots of lovely conutry to wander around. We took the bus to see Mt. Snowdon. I don't know about visiting other sites, though. The train connection was easy, too.
For public transportation, it has to be Bangor since it's a hub, but like the Bug said, there sure ain't much there. Driving opens up a whole new bunch of options.
Our Base for Northern Wales was Chester England.So if it's foal weather there are lots of things to do there. It's not that far to Conwy. We did stay overnight in Betws-y-coed...which is heaven for hikers with babbling brooks and nice woodlands. Since you are from the northwest I will tell you that most of the hills will look bare to you. Some of the towns on the north coast of Wales are tourist towns and would have plenty of accommodations in November...could be good for storm watch. Beaumaris or Caernarfon are small towns but very scenic locations. Look to see where there are "King Edward's Castles" and you should have an interesting time. The main train line to the Irish Ferry goes thru Chester and Conwy...but I'm not sure; except for excursion trains like in Betws-y-coed; if there are any other lines connecting the towns. Buses might be iffy. Consider renting a car for a couple of days.