The road less traveled by is a fancy way of saying " That road nobody takes because they're all too afraid to. "
it basically means that it's the road less taken, e.g. " There have always been two roads before you enter the town of Corydon, Washington, however, no one has ever taken to the road to the left which doesn't yet have that fancy sign like the other roads do. The townsfolk say that road leads to a cliff, and/or just drops to nothing. So one day just out of spite of all the scaredy-cats I took that road to right, the road less traveled by "
I hope this helps if any!
(A) The two men will most likely die in the woods.
