I am heading off down to Haggerston Castle at the weekend with the family.
I tend to rise a couple of hours before the rest of them so fancy trying to find tracks nearby where I can cycle out for 20 miles or so. Anyone know of anywhere?

Cheers,

Are you talking Haggerston in Northumberland? If so then I'm afraid you might struggle to put off road routes together on your doorstep. However here's a few ideas.
Cycle onto Holy Island.
Holy Island to Berwick along the coast.
St Cuthberts Cave well worth a visit.
Wooler Common to Broadstruther and back along Harthope Valley.
South of Chillingham is Old Bewick, the moor to the east, not a big area but very atmospheric and in the Northumberland MTB guide, a wee cracker.

Hope this helps.

Thank you for the input Ray.

Holy Island looks like a good option - I will check out at the others too.

: )

If you can get to the moor by Old Bewick then I highly recommend it. I did all the rides in Derek Purdy's Northumberland MTB guide and left this till last because it didn't look that good, how wrong I was, the area really is a little gem.