If you are staying in Bedugul, hiring a motorcycle is a good idea as some of the distances between areas of interest are quite long. Your hotel will be able to arrange this and you should expect to pay from Rp 50,000 to 80,000 per day.
The physically fit will enjoy mountain biking here. There are no formal taxis but you will find plenty of drivers willing and able to transport you for a fixed price.
The area is well served by local bemos, and the central gathering points for these are in and around the car park at Candikuning Market, and in the vilage of Pancasari just before you reach Lake Buyan. Be prepared for the local users to be carrying all sorts of market produce, including live chickens and other animals.