“Car” or “Caer” in Cornish is a place name from the Celtic “ker” meaning fort. You will also find Caer place names in Wales. In Brittany they use the spelling “Ker”
Caer Dane has no public access but you can get a reasonable view from the road that leads from Perranzabuloe to the fantastically named vilage of Ventongimps.
The small fort sits nicely on the hilltop and is covered with trees in the distance you can also see the larger wooded site of Caer Kief.