Not sure if this counts as epic enough, and it involves some road and the gravel is a bit chunky in places, but at the weekend we did the following in the Peak:
Hope to Hathersage via Brough and Offerton. Hathersage up to Burbage via road, permissive paths underneath Burbage and through longshaw. Bit of road to get to the Moor over Totley Tunnel. The Eastern Moors permissive paths and back to Owlde Bar via Curbar/Froggatt Edges. Houndkirk Moor, back lanes to Redmire then Stanage Pole to Stanage Causeway descent. Lane across to Ladybower reservoirs and a full loop of the reservoirs. Thornhill trail back to Hope. That was just under 60 miles and 5000ft of climbing.
When back at Hope you could extend up to Castleton broken road then take one of the bridleways off the sparrowpit road to head across the top of where you would turn off for cavedale, but carry straight on and link into bridleways back to Hope.
It’s not gravel in its strictest sense but we found it all rideable and a dropped bar bike and it was a great day out.