I used Book A Way to book a luxury bus from Mandalay to Kalaw for about 12 USD. The JJ Express bus left from the big bus station that is about 6 km from the center of Mandalay at Map Location: 21.924320, 96.088294 . I went by tuk-tuk to the bus station and it took at least 30 minutes with all of the morning traffic.
On the way to the bus station, the tuk-tuk passed an area where they create white Buddha statues of all sizes. They had thousands of statues in many little shops, in various degrees of completion, some with blocks for heads. It looks like they carve the head and face last. It would have been fun to walk through there but I could only take photos as the tuk-tuk sped by the many shops.
The bus left right on time and it was very comfortable with huge seats because there were only three seats per row. They also had snacks and a personal music and video device for every seat. I watched 'The Shawshank Redemption' and it was delightful after many months of almost no TV or movies.
We had a 30 minute lunch break at the half way point and another 10 minute bathroom break in the afternoon. The trip on the little roads was about 6 hours from 09:00 to 15:00.
In Kalaw, the Mya Sabai Inn was only a few blocks down the main highway from where the bus dumped us out. I checked in and went for a late lunch at a tourist restaurant and then walked up a hill to a temple that had a nice view of the town and the valley. There were also a few temples in the center of town that I went through.
Later I went to a motorcycle and bicycle rental place and reserved a motorbike for the next day, 10 USD all day, not including gasoline. They don't open until 08:30 so I can't leave extra early like I prefer to do.