Visited 22.08.19
I parked at the Kintra campsite. I had to turn back at the ford to get my wellies and stick for the burn crossing. They came in handy later. Frachdale ruin was easily reached and a rough road ran up the hill to Frachdale Chambered Cairn and Coille A’chnoic Mhoir standing stone, easily spotted a quarter of a mile up on the right. As drewbhoy observed Frachdale Chambered Cairn was less accessible. I went through the gate at the top of the hill and followed my GPS South down a steep ferny slope crossing a boggy valley to the summit of the mound. The cairn itself is vegetation free, unlike its surroundings. I retraced my steps to return, avoiding further adventures.
Canmore ID 37607 (go to Links) give further details of Frachdale Chambered Cairn.
Very beautiful area!
Islay has many beautiful sites. I'm following in your damp footsteps... I will be back next year to continue the quest.
I hope you don't follow all of my footsteps :-) Intending going back next year as well, but basing ourselves in Jura :-)