By car this journey would take around two and a half hours so by public transport you're going to be looking at much longer. Long distance to travel just for a day. It might be an idea if you're going to do this trip to book cheap accomodation in Hisaronu and stay overnight.

hi we have done this a couple of times have family in marmaris but we like olu and fancied a change,the drive in a car from olu to marmaris takes 2and a half hours it is a straight run which only gets busy round fethiye centre/marmaris centre.you can book a coach at the shops behind marmaris tansas it costs about 18 lire and takes around 3 hours the coaches depart every hour or maybe more frequently depending on the time/day.travel republic/on the beach/hotels4u offer very very good value for money accomadation that you can book online for one night or more goodluck