We visited these two as part of an abortive attempt to see if we could get to Ormaigwith the kids in tow. Didn't get to Ormaig, but it was still worth the walk, goodly sized, stately stones, and a nice view.
From the look of things, it could be a bit of a faff to get here from the castle car park. The 'pasture' field that you have to cross is no longer pasture, and I couldn't see a gate anywhere. The path that leads up from the south was no bother at all.
Very late addition here (it's about six months since my visit), and I don't know why I haven't posted notes yet... here goes then:
The path leading to these stones can be found by following the sign posts up to Carnasserie castle. While here it's a good idea to take a look around the castle - the reason being, it's possible to see the stones from the SW tower, and it'll make the journey much easier than plodding round the fields aimlessly!
When I visited it was raining, not very hard, but enough so I had my hood up. As I explained above, I worked out the direction to these stones by looking from the castle tower. The castle was very atmospheric, and in the rain it's open roof led an eerie atmosphere to the place. Excited by the sight of these two stones, I span round quickly, ready to jog back down the wet spiral staircase steps. A lintel, unseen due to the peak on my hood, blocked the way. Crack! I smashed my head on it and tumbled down a few steps. I landed with a thud and a very sore head. A bit dazed, I shakily proceeded down the steps. Now this castle is in the middle of nowhere really, and I began wondering if I'd been knocked out, or anything more serious had happened, who'd have found me? Once I reached the bottom I sat down, stars spinning before my eyes, rubbing the nasty lump which had by now appeared on my head.
I soon decided to carry on regardless and made my way to the stones - they were wonderful and I soon stopped feeling sorry for myself as I became acquainted with this pair of fine standing stones. Anyone visiting the Kilmartin valley would do well to track these down - it's roughly a 3/4 hour round trip on foot from the car park, just off the main Kilmartin valley road. Carnasserie cairn lies just above the stones, and as a wise Welsh farmer once advised, it's best to follow your nose to find it. Once you do, and if it's clear, you'll be blessed with a stunning view down the valley to the Nether Largie cairns. This cairn is almost in the same line as these, and if you look behind you you'll see the huge cairn Càrn Bàn on the horizon.
I'd definitely recommend this site, just watch for stray lintels would be my only advice.