A few suggestions to the route:
http://www.bikehike.co.uk/mapview.php?id=29962
Instead of Mam-tor straight to Dirtlow Rake/Pindale, go up onto Rushop Edge and down, then round on the backlanes (includes a very fast backlane, usually very quiet)
Instead of Hope Brink (lots of snow melt* wet grass) you could go up the Roman Road out of Hope
Instead of going up blackley hey, you could go up the long strightish up in the woods used last time, coming out part way up win hill, then take the fast grassy down back to hope cross (then back in edale)
*assuming the snow has actually melted a little, if at all ..
EDIT: Whoops, bikehike says its 24miles ..
I've done it before, its not that taxing, its just 4 hills spaced out a bit more than a typical peaks ride