Once here, you'll find renting a car allows you to get around with the most ease; many of the sights you'll want to see are off the main roads, and the area is filled with beautiful coastal drives.
Although the highways between towns are well maintained, smaller roads can be unpaved and rough and the twisty coastal roads require concentration. To estimate driving times, figure on about 70 km (43 miles) per hour. Driving from Istanbul to Marmaris or Antalya is at least a 10-hour, 750-km (470-mile) trek. The speed limit is 90 kph (56 mph) on most country roads—120 kph (75 mph) on real highways—and for your own safety it's best to stick to it. The police have radar devices and they do use them.
All airports have several car rental agencies to choose from; many hotels can also arrange rentals. In general, the smaller and more remote the place, the cheaper the rental, but the more minimal the service.