The minor routes are the picturesque and involving one's for sure.
I try to avoid the A9 when going to Dingwall and either go via Glencoe or Creiff.
Yes if I'm going to Plymouth for something I go via Dartmoor the A38 is just like the A9 a pain and boring as a digestive biscuit..
That way I'm guaranteed to see Dartmoor ponies, Dartmoor Blackface sheep, Belted Galloways, Highland cattle and occasionally a deer, so there really isn't a choice is there

we are very lucky as it's only a 30minute drive away.