I agree with Del that Kalkan is hilly and I am not certain it would be suitable for children as it is very quiet and laid back...depends what they like to do on hoiday.
We have been going to Kalkan for the past couple of years and will be back next week. We stay in a lovely hotel but could be a bit boring for children although great for adults. It takes us about 10 minutes stroll down to the harbour and it is quite a steep walk but we get a taxi back,,,but then we are not youngsters.
Our other favourite resort is Icmeler which I would say would be ideal
for children, no hills, beach close by, plenty of apartments and loads of places to go to.
It all depends on personal choice