Thailand and Bali Honeymoon in March

So, I am thinking about a 3 weeks honeymoon (2 weeks Thailand and 1 week Bali). Actually, I have even more time since I took almost 5 weeks off work but could cost more traveling for long.

My initial plan is as follows.

Thailand: – Bangkok 2/3 days (day trip to Ayyuthaya included – Fly to Chiang Mai for 5 days (elephant sanctuary visit) – Fly to Krabi or Koh Samui for 5 days ( take day trips to phi phi island and do some water based sports such as scuba/parasailing.

From Krabi or Koh Samui we can fly to Bali.

Bali: -3/4 days in Ubud 3/4 days in Seminyak

How does this plan look like? Any places or activities you suggest. Also any accomodations/hotels/resorts ? We want a mix of nice and good enough places. Since it's almost a 3 weeks trip so I don't want to go overboard or super luxurious and would like maybe more to spend on activities.

I don't want crowded places since this is our honeymoon. Would you suggest Krabi or Koh Samui or something else altogether?

I was thinking to add Cambodia but maybe it will be too much. We will be flying from South Asia, so flights are not super long like in US.