Any C2C that includes the Lake District, the Yorkshire Dales and the Yorkshire Moors is always going to get my vote.
I’m not au fait with the road to the west of Sedburgh, but I do like your route from there to Leyburn. However, to the east of Leyburn the A684 gets a bit busy for my liking (at Easter I even went through Preston Under Scar and down Whipperdale Bank to avoid the main road from Wensley to Leyburn – although with hindsight that could have been a bit too cautious after all).
I rode the A684 from Leyburn to the turn off to Harmby and I found it hard going with a lot of traffic up until that point (I was very relieved to get off the main road).
However, If you would consider going in a north-easterly direction from Redmire, later going along the B6108 for a few miles before taking the quiet roads to Richmond, then there is a less stressful route you could take to Stokesley. It’s a bit circuitous from Richmond - and there’s an easier way to Moulton if you wanted to go that way at all - but if you could find the time for the extra distance I think you would enjoy it. Here’s my Richmond to Whitby bit:
http://www.mapmyride.com/ride/united-ki ... 1886319460Last October I more or less did your route from Stokesley to Whitby (actually to Lythe just to the north of Whitby) in the opposite direction - or at least I tried to, but the satnav took me through Westerdale:
http://cycleseven.org/westerdale-sat-nav-hills - and it was very pleasant. (Apart from Westerdale, thank you.) But I avoided as much of the A171 as I could. I would advise you to miss out that stretch, too, if possible. (I took the A174 and that wasn’t so bad. If, for instance, you went as far north as Lythe you drop like a stone in to Whitby from there.)
So, basically, I think there are - for my taste - a few too many A roads on the route as it stands. If you’re okay with that then go for it. But if you want to spend perhaps a bit more time on a long summer day enjoying quiet, pleasant roads then maybe you could look at taking an alternative route.