I'd recommend Ripon Runners too. They are a really welcoming bunch and they train on Tuesday and Thursday nights. Lots of fell, long distance and ultra runners in there too. Nosemi, Masham Man and Fairyfeet are all from Ripon.
I run with Thirsk and Sowerby but have hooked up with the runners from Ripon to do long stuff on a weekend a few times. Last winter we had a cracking run through the snow from Galphay over the moor and down into Pateley along the river back up via Brimham and back to Galphay. Masham Man also organised a great club weekend that took in the LDWA Four Lakeland Passes staying in the hostel there. People of all abilities went.