Possibly something to avoid (or investigate further):- With only a few hours available a few years ago we were borrowing one of David Hall's routes which was around Skelwith Bridge/Farm etc.
Part way around we began to notice green static caravans through the trees and thought they seemed in an idyllic spot.
Further round we began to see more of them and then realised it was quite heavily populated
Just looking now on Google Earth, it doesn't look as bad as I remember. That was Skelwith Fold caravan park.
Another I used to see regularly was Limefitt Park, which is just a little NE from Troutbeck off the A592. Unable to make a personal recommendation but a lovely location, if just off the central spine you are aiming for.