Raedykes is a bit of a misnomer; Raedykes itself is a Roman camp on nearby Garrison Hill, while the ring cairns are actually on a different hill, Campstone Hill. There are four ring cairns, one obvious, one less obvious and two dubious. The most intact cairn, on the very top of the hill, features three large stones which Watt* suggests could be "the precursor of a great recumbent stone circle without a ring cairn", the kind of circle most prevalent in this region.
The choice of location is obvious, commanding a great view across to more modern monuments in the form of the masts on Cairn-Mon-Earn and at Durris in one direction, and Stonehaven and the sea in the other. The nearby Hill of Cairneymore, as the name suggests, would have been a superb source of materials.
Getting there: Take the A597 out of Stonehaven for just over 3 miles; you'll cross one bridge, the Findlayston Bridge, about half way there. Eventually you'll come to a place where there's a turn off the road to the right, up a small hill, with a post box in the wall on your left. Go up this hill and you'll quickly come to a fork in the road.
If, as I did, you want to access the cairns via the Roman camp, carry on up the hill (right fork), and use a map to get across to Campstone Hill! This is an interesting way to go, as you'll go through Cairneymore Hill - which is fairly obviously the source of all the stones in the cairns.
If you want to go straight to the cairns, take the left fork, and carry on until you're looking down on a small cottage, called Union Cottage. There should be three green gates in a 'T' on your right; follow the middle of the 'T' up to the crest of the hill and you're there. Either way, taking an OS Explorer map is a very good idea.
Notes from the proceedings of the Society of Antiquaries of Scotland from December 11 1922
on Raedykes northern Stone Circle and the inner Stone Setting, together with the Ogam inscription which is incised on its southern side.