The loop Garry suggests is better done the other way around in my opinion. Starting at the North-east end of Wastwater, take the bridleway to Burnmoor Tarn (hard to make out the path the higher you are, you’ll have to climb over a fence and stay to the right and above the Tarn), then a fantastic long exposed downhill into Miterdale, then either to the road or better, take the forest track up to Irton Fell and down the other side towards Nether Wasdale, but that is VERY steep/unrideable in some places (for me, at least) but very nice.
Just about to reply to the other (Eskdale Green) thread. Happy to chat tomorrow, Garry, as well…
I don’t have GPX files, but while shorter, the route above is mainly ridable, whereas everything that leads North or East from Wasdale Head will involve a lot of hike and bike.