HELP Bangkok, Koh Phangan, Koh Samui, Kuala Lumpur, Singapore in15 DAYS

Hello all.. Currently planning our 15 day (roughly) honeymoon through south east Asia. I don't know if I am trying to squeeze to many locations in such a short period of time. Flying from NYC to Bangkok on august 18th (landing bkk 08/20 12am). Looking to stay in Bangkok 08/20-8/24 (4nights) see the city etc. Then fly to Suranthai (Asia air) and make our way (ferry) to Koh Phangan 08/24, and staying in Koh Phangan 08/24-08/28 (3 nights), then over to Koh Samui for 3 nights 08/28-08/31. From Koh Samui well ferry back(5am) to Suranthai and fly to Kuala Lumpur(asia air), spend 2 nights in Kuala Lumpur, then fly to Singapore. Spend the next day/night in Singapore. Then fly back to US from Singapore. Is this too much traveling for a honeymoon? Should we spend more time on one of the islands relaxing or maybe an extra day in either Kuala Lumpur/Singapore?

In Short:

Bangkok- 4 nights
Koh Phangan- 3 nights
Koh Samui- 3 nights
Kuala Lumpur- 2 night
Singapore- 1 night

I Have never been to Asia, and put this together simply by looking through tripadvisor/blogs etc and figured I might as well post my plans and see what the "experts" think. Any and all suggestions, including excursions, dining, things to do would be greatly appreciated. Priced/picked hotels for all locations. From what I have read/seen Asia Air has some really great prices for flying. Haven't looked much into Kuala Lumpur/Singapore.. was merely a means to the Marina Sands hotel before flying back to US (chance to see another city instead of Bangkok before flying home).

Thanks in advance!!

Three letters... OMG.

To make it list of a rush. Maybe you could stay in just Koh Samui? From Samui, you can make day trips to Koh Phangan and even Koh Tao.

Just a suggestion.