On the first day of the tour you need to be in Kas. Therefore, you can arrive there the day before from Antalya or Dalaman airport; the journey will take 3-4 hours by public transport. You can also arrive to Kas early in the morning on the first day of the tour, but it may be difficult as the day is busy. NOT RECOMMENDED :)
Return: the tour ends in the evening, tickets from Dalaman can be taken from 20:00, if you are flying from Antalya - the next day.
You can take air tickets without luggage and get by only with hand luggage, since you only need to take comfortable summer things with you :)