Do you know where Portobello apartments are?
If yes they are right beside them. 5mins to beach
Or if you walked along the main road in marmaris... there was a statue of Elvis stood outside a bar... they are behind there.
If i remember right they are number 158 on the map of marmaris, you will have to search for it on here.
Tell your sister they are nice aparts, ive stayed there and always visit, my sister also stayed there last year.
Hope this helps.