Yes, it’s worth it and Tunnel Hill would be my suggestion.
I would suggest to park here – there’s a large layby where the arrow is.
http://www.streetmap.co.uk/map.srf?x=491857&y=155877&z=120&sv=491857,155877&st=4&ar=y&mapp=map.srf&searchp=ids.srf&dn=722&ax=491857&ay=155877&lm=0
From there, head NE down the hill slightly (on road) to an obvious left turn which drops you down and under the railway. Turn left and follow this gravel road to a major turn on the left, follow this up a hill keeping the railway on your left and climb gradually right to the ‘ridge’ that runs NW to SE through the area (unmade Byway on the map)
This climb was part of a fairly recent Gorrick race so from this point you can still if careful pick up tracks which will lead you around a 4.5mile loop as a start. Or you can just ride around heading down likely looking paths. There’s loads up there and some real ‘not even hidden’ gems too. Majority is in the area in the bottom left corner of the linked map, but there’s enough all over to fill 2 hours easily.