Fabulous riding there, I love it.
@pook is a guru on the area organizer of peak pootles
25 miles in the Peaks means lots of climbing so that’s a very solid ride (I think the loop below is less than 20 and would take me 5-6 hours)
Hope Bikes sells good guides of the area (Dark Peak) plus loops shown on maps in the shop.
From @pook I got a few routes but one good un was
Eadale (large car paid park – National Trust cafe) to Hollins Cross, Mam Tor, pickup Limestone Way to take in Cavedale descent to Castleton, climb landslipped road back under Mam Tor to Rushup Edge, Roych Clough/South Head on Pennine Way, climb to top of Jacob Ladder, great rocky descent over all too quickly (don’t miss bridleway and take paved footpath = booring) and back to car
If you email me (in profile) I can send you a map
Ladybower a few options available which take in “The Beast” descent plus the obligatory photo stop at the National Trust sign at Winstone Lee Tor