Hi Kerry,
Welcome to Club paradise

, the weather will be great at start of june, very warm but not scorching hot. as for the kapmar, its had many great reviews and spot on location so you have picked well I think.
Icmeler is not rowdy at all, depends on what you are looking for and what your group consists of. there are plenty of great restaurants and bars for you to enjoy and have fun at, you will probably find your favourites quite quickly. I have also been to Hisaronu & Olu Deniz and Icmeler beats it hands down, Icmeler has a certain je ne sais quoi, great size, great people, great food and all round very pleasant ambience and nothing ever seems rushed, it can be as lazy or as active a holiday as you wish it to be, and
Marmaris is only a dolmus away. it is a fair distance from airport so I would advise a speedy shuttle, as opposed to a coach, if that's practical, or even a private transfer. look forward to reading your thoughts, oh, and once you have been it is almost certain you will want to return, and remember your visa !!