I was thinking along similar lines, Wow, except going via Scotch Corner so we can take advantage of a sit-down and a coffee at the 24 hr services. Then along the quiet A-roads and b-roads to Reeth, and up Arkengarthdale to the pub. There's probably even less climbing than in your original route (since the Vales of York and Mowbray are rather flat places). I'll probably have to book breakfasts at Tan Hill in advance, but in my experience this is the sort of slightly bonkers endeavour that the folk at Tan Hill would greatly approve of.
How about early July? That leaves May and June free for FNRtSR Scarborough and elsewhere.