Trip reports forum

Hello,
I am traveling with my girlfriend from California to Southeast Asia in January/February (~55 days).  Below is the itinerary we were thinking about following.  I was looking for some thoughts from experienced travelers to this part of the world if this is possible, or if we should thin it out a little:
Vietnam
1. Flying into Hanoi (2-3 days)-- Ha Long Bay (3-4 days)
*1 Day Bus to Phang Na or 1Hr Flight*
2. Phong Nha/Ke Bang National Park/Hue (3 Days)
*4 Hr Bus or 2 Hr Train to Hoi An*
3. Hoi An/Da Nang (2-3 Days)
*Flight to Ho Chi Minh*
4. Ho Chi Minh/Phu Quoc Island/Mekong Delta (2-3 Days)
*Flight from Ho Chi Minh to Phnom Penh *
Cambodia
1. Phnom Penh (1/2 Day)
*4-5 Hr Bus to Kampot *
2. Kampot (3-4 Days) 
*4-5 Hr Bus back to Phnom Penh*
3. Phnom Penh (1/2 Day)
*5 Hr Bus to Siem Reap * 
4. Siem Reap & Angkor Wat (3 Days)
*Fly from Siem Reap to Vientiane *
Laos    
1. Vientiane (2-3 Days)
*4 Hr Bus to Vang Vieng *
2. Vang Vieng (2-3 Days)
*8 Hr Bus to Louang Phabang*
3. Louang Phabang (2-3 Days)
*Bus, Train or Plane to Chiang Mai *
Thailand
1. Chiang Mai (3-4 Days)
*Overnight Train to Bangkok*
2. Bangkok (1/2 Day)
*Fly from Bangkok to Krabi*
3. Andaman Islands (5 Days)

From here we were thinking about flying to Bali/ Lambok for ~7-10 Days if we have time before flying to New Zealand.

Thanks in advance for your responses!