>>You're thinking of a different cam Ye O'er, or a different Rocky Road, or perhaps both.

Eh, I don't think so. I've pretty comprehensively gone through all the folktunes.org midis and recordings on Youtube.

The Fiddler's Companion lists a few different songs that sound like it, but Cam Ye O'Er Frae France isn't one of them. (And then again, none of those sound very much like Rocky Road to Dublin, either.)