For the cruise, the distance isn't the major factor, it's the traffic. It can be a nightmare when it's bad, about 30 minutes or so when it's good.

As to currency, you can exchange dollars into their Lira just about anyplace. Expect very long lines if doing it outside of the airport, as many people there are turning their lira into dollars. When we were there a couple of years ago (cruise), it was no problem getting money converted, and many many places will take dollars, as others above have said, sometimes at some very good discounts.

The dollar goes an incredibly long way there, so don't exchange as much as they think they will need.

The exchange rate is over a million lira to a dollar now, and on some of the bills the last three zeros are a different shade, so make sure they get the right amount of money. The currency places were fine, but sometimes the little local stores were a bit less concerned with making the proper change for tourists.