My suggestion would be to start straight with Chiang Mai. 2 years ago we flew there non-stop from Taipei on Asiana, so avoided Bangkok.

3 nights at the MO Dhara Dhevi

3 nights FS Tented Camp

Get a private boat on the Mekong to Louangphrabang, Laos (definitely not many tourists on this route)

2 nights Amantaka

If the flight connection is ok, I'd try to include Siem Reap. Tourists or not - Angkor Wat is a must do IMHO for Asia 1st time.

2 nights Amansara

The rest seemed pretty much set for you ...