Hi Moira,
The weather end of Sept begining of October is normally changeable, nice during the day but can get chilly at night.
As for the transfer with the tour operator, this is entirely up to you, A private transfer to Olu deniz is about 1 hour 20 mins, the tour op transfer could take considerably longer because Olu Deniz is the last stop off point and coming back it is the first collection point, so the normal transfer of about 1 hr 20 min could quite easily turn into 2 hrs 30 mins.
As for a taxi from outside the airport leave them alone, they will cost a fortune, there are several companies that offer private transfers if you wish to look into it, I myself could arrange your transfers for you, the cost to Olu Deniz from Dalaman Airport ( up to 4 people ) is £ 80.oop return.

Kev

when we stayed at lykia we got private transfers with orange cars as lykia will be the last stop as its slightly further than olu deniz is and it will be the first pick up this could add another hour at least on to your journey so its entirely up to you. we loved lykia its fantastic so i know you will have a wonderful holiday

We have just come back and had booked a cab with orange transfers but unfortunately it was the Lykia Express - no drop offs with Thomas Cook so we could have saved ourselves the cab fare. You live and learn, however on the way back we were first in the check in queue.