Amber valley is a walking area I really rate. Plenty of footpaths, most of them quiet, beautiful scenery, and if you get temporarily misplaced, just drop down into valley bottom, and pick A6 or railway station for a ride back to Matlock/ Derby (whatever)... excellant public transport.
Most of the walks I've done last few weeks have been 6 milers in the area, starting from Duffield, Belper, or Ambergate. And next time, I do a long walk, plan is to just get off train at Duffield, and start walking towards Matlock, to see how far I can get before relenting and catching a bus or train back.