Can't help myself from adding one relevant and one irrelevant suggestion!

1. Between Ab. and Thurso, if possible, try and look up the Templestone site. (Listed here.) It's just a stop-off, perhaps, but we were enchanted by the then owner, Caroline Dunnet. Probably by now it's someone elses' property. Nice castle over the little hill in the background.

2. Relevant, if you haven't already added it. Isbister.

3. The irrelevant. While on Orkney, visit Jolly's of Orkney. Kippers to die for!