Tour de Yorkshire: local knowledge sought

IIRC. The very last drop from Park Rash is a nasty 1:4 to 1:3 with two almost hairpin corners from relatively fast sweeping left almost blind. I tried riding up it and ended up crying is was that bad.

Aysgarth, Hawes and Castle Bolton are busy tourist centres so could be fun.

Pretty obvious - but the descent of Buttertubs needs care. Particularly the T-junction at the end!

The descent from Park Rash is steep. Make sure you all have good brakes.

None of the roads on your map I'd say are that busy. The B6160 around Threshfield can be quite active at peak day-tripper arriving/leaving times.

It must be one of the most beautiful 78 mile loops in the UK. Enjoy!

The Dales Bike Centre cafe would make an excellent half way stop. It's just after Reeth.

Not a local but rode some of that recently. Those roads are plenty quiet enough. Only thing I'd watch riding in a group, is that the B6160 narrows to a single lane as it twists through Starbotton - go single file there and you'll not get jammed up with oncoming cars. It widens again outside of the village.

You'll get dropped... on the hills :D.

But why don't you take a look for yourself -
http://www.brianfolts.com/driver/#origin=Threshfield&destination=Aysgarth

that site strings together Google Streetview images so you can pre-ride a route. Because you can only specify the start/end not the roads, you have to do this in several chunks to get it to follow the route you want. I used this to check out roads for a tour of france this year.