I can suggest a little diversion on your route which might just blow your socks off.
A 15 mile drive North up the A68 from Hadrian's Wall North of Corbridge will bring you to Rochester. Head down the A698 past Otterburn and turn off towards Hepple. Park at Billsmoor Park and head up the footpath towards what is marked as "The Pedlar's Stone" on this map...
What you are looking for is NOT immediately easy to locate. Indeed it was only "discovered" fairly recently. You can orientate yourself using this photo which looks towards North Yardhope.
There are many rocky outcrops here. Persevere. You'll find it.
Look upon the Shrine To Cocidius.
Enjoy your trip.
HD