As mentioned – Eltringham Woods (behind Hammerite), Prudhoe Hall Woods, Hyons Wood, Whittle Dene – can all be linked up if you don’t mind the odd road section.
I tend to go along Edgewell House Road towards High Mickley, then down Lumley’s Lane to the old pit and have a blast around there, then along Hyons Wood to Moor Road to do Prudhoe Hall Woods for a bit.
Then come out on the A695, back towards Mickley, then down to Eltringham Woods and the Riverside Park, along to Wylam. Cross over the river at Points Bridge then up into Horseley Woods. After that, Ovingham, up into Whittle Dene to the top, then hoon it back down, over the river and back up the hill to the top of the valley then home.
Might be able to make it out at the weekend if you fancy a guided tour.
Edit: sounds like there’s a few of us who know the area – I’m from Ovingham and been riding all of the above since 1989!