Wow, Cambodia. Laos & Vietnam in 19 days! Not very laid-back.
You may need NASA resources and precisions or a top-class tour agent.
Luang Prabang is never enough in Dec (4-5 days )
Angkor Wat/siem reap needs 3-4 clear days
Hanoi/Sapa/Halong is a rush if you have less than 8/9 days and that doessnt leave much for HCMC, Hoi an and the MeKong Delta and the beaches
but then, it's your time and budget.
I think you should be thinking of returnibg even before you leave these places.
#3 KPTham1 has been a member since 26/9/2006. Posts: 52