Lock your doors!
Seriously it has some seriously pretty beaches but most of them have signs to say they've had nuclear particles washed up on the beach. Whilst many ignore this and walk the beaches, and they're really beautiful, I consider them dangerous. A colleague that lives in the area has two dogs that have died of cancer of the mouth, I can't see that as a coincidence. Further along the north coast there's Smoo cave, to the south of Wick there's a wee remote fishing 'harbour' that is accessed via a long steep set of steps. Sorry I can't remember it's name. I've travelled the area extensively for work and would add caution about Berridale Braes north of Helmsdale. It's like something out of The Italian Job, go round in first or second. If you fancy coming off the coast take the inland route from Helmsdale to the north coast. It's a wonderful road through an RSPB site and I remember a few handy wild camping sites not too far off the road. Lots of deer and big reds not wee roe deer. The road is mostly single track so match your speed to how far you can see in front of you. It's all moor and likely to be wet after the weather we had last week. The temps don't look too bad beneath, 10ºC but you'll know yourself that it can get a lot colder than that locally. I used to be there a lot so it was very familiar to me and I don't remember Wick or Thurso having much to attract barring shops to re-stock and re-fuel. The fuel will be expensive btw. Duncansby head and Dunnet head are nice for a view, John o Groats to tick a box, the stacks from Duncansby head are nice for a photo. Helmsdale has an emigration statue just as you enter it. On a lay-by between Invergordon and Wick there is a stone laid with a claim that the last wolf in Scotland was killed in the area. The area surrounding the A9 is mainly farmland so not a lot of remote places to camp.
That's a bit of a ramble, any questions let me know.