Yes it is quite simple. you catch the dolmus from
Icmeler and where you get off in
Marmaris you catch another dolmus to the otogar which is at the very top end of Maramaris as you leave the town as if you were going to the airport. From there you catch a bus to Fethiye and get off at Otaca, about one hours travel. From here you will catch the local dolmus into Dalyan. A good day out and not expensive. Just remember Turtle Beach is a separate Dolmus ride away and takes about 10minutes