If it's during the holiday season, no problem as the dolmuses run quite late. From Olu take the dolmus at the bottom of the hill direct to Fethiye. If it's for Calis, you can 1) stay on to the terminus behind the mosque in Fethiye & get the Calis dolmus there 2) get off just after the roundabout just past the otogar & Carrefour, cross the road & catch the Calis / Gunlukbasi dolmus or 3) get off at the Migros crossroads, walk around the corner & get a Calis sahilden dolmus.