The superintendent of Westbrook schools is the leading candidate to be head of the Mount Desert Island Regional School System. Marc Gousse, who was the principal of Westbrook High School for 10 years and has been superintendent since 2011, will visit the Bar Harbor-based district to meet administrators, staff members and the community on Thursday. Charles Wray, chairman of the district’s school board, said other candidates have not been eliminated but Gousse is the only one who has been invited to visit the district.