Hi Ian and welcome to RB.
Thrunton is a big place and there is something for everyone from fireroad, moorland XC to nasty bone breaking DH. We ride there most weeks- usually Tuesdays and Thursdays. No problem in showing you around just keep an eye on the NE Nightrides thread.
Plenty of other things going on too- see the Calendar. Weekend rides are to cater for all tastes and the routes are pretty easy- 25 miles max, mainly off road and on mixed trails.
There is also a local group based in and around Morpeth called the Muddybums with whom I ride occasionally. They do big epics in the Cheviots at the weekends but steadier social 'Bimbles' on weeknights. Again a friendly bunch who warmly welcome new riders along.
As for singletrack we are spoilt for choice. As well as Thrunton there is some great stuff in Simonside and around Morpeth, Wansbeck River, Coquet, Hartburn etc.
Nothing much happening this week as I'm going down to the Peaks on Saturday but could be up for a ride next wed or thurs. Simonside could be a possibility??
Si