Below are two very different bikepacking routes, which offer different challenges in terms of length, amenities and terrain.
Both are difficult, and you will need experience riding off road with a packed bike.
They do have train stations at either end, which should make transport and logistics easier for anyone wishing to do them (assuming the trains are actually running…).
100 Miles. Macclesfield to Betws-Y-Coed
30 Miles. Macclesfield to Edale