In reply to Mike Conlon:
We've had a good week, most stuff should be dry. It's looking breezy but not too bad so anywhere should be viable from that POV too.
Depending on what low to mid grade mean (VD-E2? trad) Bowden is the best crag in the county and one of the most best in the country at those grades. Personally I'd do a day there and then have a think, personally if I was a first time visitor I'd probably go back the next day and tick a bunch more stuff. Personal faves: Russet Groove, the leaning grooves, Tiger Wall, Banana Wall, Main Wall, Crunchie, probably a bunch of others I've forgotten.
Kyloe out's probably the next best for low-mid trad and you could easily spend a day ticking classics there: Flake Crack, Tacitation, Wilfred Prickles, Devil's edge, back to the egg... If you're bored or it's busy then Bowden and back bowden are 10 mins drive away.
Corby's and Berryhill are both great crags but they'd not be might first choices.
If you have a mat, take it. Northumberland has some of the best bouldering in the country.
Post edited at 17:40