Hi Laura
Armutulan is in a quiet area of Marmaris, i wouldnt advise you to walk it to Icmeler, that would probably take around 45mins - 1 hour depending on how fast you walk. The dolmus runs from Armutulan to Tansas, and then from outside tansas to Icmeler, and its really cheap as well.
Hope that helps
Heather
ICR Representative