How to Travel?
Despite of being developed tourist destination, the public transport is virtually non-existent or whatever is there is not very tourist friendly.
Very recently a bus service targeting the tourist has begun in central & south Bali and the name is Kura Kura. There are 2 flip sides of this service though, first is the frequency of the service and second is the operational hours.
But still there are many options of travel are available for tourists, like, hiring a cab (using Grab or Gojek Apps) or just flag down a taxi on the kerb (this involves haggling) or renting a two wheeler for the day, the rent for the day is typically between 300-500 Rs, I found this to the best option if you are going to travel just about 60-70 KMs in a day and comfortable riding. Bike is easy to navigate in the narrow roads and in traffic jams, which is very common in Bali.
If you are not comfortable riding, then you can hire a car with or without a driver. I would advise strongly to hire a car with a driver you are planning to cover places which are distant and total travel is going to exceed 70-80 KMs for the day. Driver makes your life easier, as you would not have to look for parking space and navigate in narrow streets. On top of all the driver can become your guide too.
The easiest way I found to book the cab for the day is on Grab App, they have an option of hourly hire. The prices are reasonable too, for half day it's around 1500-2000 Rs and for full day for entire island, it's about 3500 Rs. You may also try other apps like, Klook.
Although, as a rule it is mandatory to carry International Driving Permit to drive a car or ride a bike in Indonesia, but if you are following traffic rules, then nobody checks the paper in reality.
What to see & do?
As I have earlier also mentioned that Bali is a complete package of a lot of things.
To make your life easier, I have made a list of Top Ten Places (Places not to be missed). And here is the video-