Mad,I don’t do Bivying! I will be staying in a nice heated cottage in Ambleside half term week. My favorite route ever is going from Windermere and up over Garburn Pass and then finshing in Ambleside, and refilling with the best choc brownie in the world at the rattle grill cafe behind the tourist information centre in Ambleside!. I do it as a day ride.
If you want the route I can share it off my memory map thing! Where in Mid Wales did you go? I live in Llandrindod Wells!