Lumsdale n Cromford look interesting, I've never been to either.
Both well worth a mooch about pleb. There are actually a few nice walks that start in Cromford. You may have heard of Black Rocks? One option is to stroll by the canal until you reach High Peak Junction (Lee photographed the old railway carriage there) and climb steadily up to Black Rocks via the High Peak Trail.
I usually follow the trail all the way up to Middleton Top, but then veer off and loop round via Bonsall and high above Matlock Bath on a circular route back to Cromford.
Lots of interest along the way!