I live in the area so take this with a pinch of salt
In the Dales because there's so few roads, the "main" roads are surprisingly busy and depending on time of day have varying levels of pleasantness on a bike. This is the route I'd take.
Clitheroe - Waddington - Grindleton - Bolton-by-Bowland - Halton West - Nappa - Gargrave - Hetton - Cracoe - Linton - Grassington - Conistone - Kettlewell - over Park Rash and down Coverdale to Agglethorpe - Wensley - Leyburn - Grinton. There's not many realistic options heading up Swaledale but the B6270 isn't that busy so I'd follow it all the way to Nateby. From there to Helwith Bridge there's really only one road that you'd be taking. At Helwith Bridge there's a minor road on the west of the Ribble into Settle that's nicer than the main road. From Settle, head to Rathmell, Wigglesworth then Bolton-by-Bowland to pick up your outward route.
