Loie and I did Sardinia last year, which is not Corsica, I know. But based on Sardinia, our best advice would be "Start with the maps, and ask for directions." If in doubt, just show your map and point to the name of the thing. Most of the time, someone will lead you to it, even if they have to get in their car and drive for you to follow them. Really. I'm sure the Folks will have a lovely time.