Thanks for the responses, all! It is good to see that sequence association saves the day here for going from F --> C. And thanks to @ivanpribec for the link to the F202x proposal for facilitating C --> F.
In the standard excerpt that @lkedward quoted, I take it that sequence association used in this way still requires that the Fortran character variable be of kind c_char or an equivalent. I wonder if there are any machines out there (running, not in museums) where default character kind and c_char are not the same?