By STEWART CHISHAM - NEWS EDITOR What started as 115 writers crammed into a one-room lodge has exploded to a 300-person literary getaway that's emphasizing Okoboji's place on the map. The Okoboji Writers Retreat returns Sept. 28-Oct. 1 for its fifth year, bringing Hollywood directors, Grammy-nominated musicians and bestselling authors to the shores of the Iowa Great Lakes Region. Registration costs $795 with early-bird pricing through July 15, jumping to $895 after.