KRS

We are arriving into TPE on 21 December and departing BKK on 30 December (part of a TPE-BKK-HKG trip with a stopover in BKK).

The plan is to spend a couple of days in Taipei, and then fly to Bangkok to commence a trip eastwards to include Siem Reap, Phnom Penh and Ho Chi Minh City (Saigon). To connect with our flight out of BKK we plan on booking a separate Air Asia flight from SGN til BKK on the morning of 30 December, with several hours layover for contingency and F lounge access

Questions are:
is this too ambitious?
Other sights that we should consider instead?
Spend more time in Taiwan? (all reports indicate that it is worth a longer visit than a couple of days...)

Note though that Angkor Wat is the top priority...
Also, we are not planning on spending time in Thailand on this trip as we have been before and consider it an easier destination to get to compared to Taiwan and Laos/Cambodia/Vietnam/Burma. Having said that we could also consider heading North to Chiang Mai/Chiang Rai/Vientiane/Luang Prabang instead...

All suggestions welcome!

jiejie

Don't like your plan. You're not going to have much meaningful sightseeing time except in transport hubs. Way too much crammed into little time, and some unnecessary criss-crossing of SE Asia. And never, never take an Air Asia flight where you must connect on the same day to an unrelated international flight. Those "contingency hours" have a way of disappearing quickly. Keep things simpler and get the priority of Angkor in earlier.

I would dump Vietnam plans totally for now and put it on a dedicated future trip. It's silly to go to the trouble of getting there for just one city for 1-2 days. If Cambodia is the priority, don't dilute it. Fly directly to Phnom Penh from Taipei (Eva flies a daily morning flight, I believe). Then to Siem Reap. Then either to other locations in Cambodia or to Bangkok. I think time you decide to spend in Taiwan is one determinant. Example:
4 days Taiwan (including arrival)
1 day flight TPE-PNH, onward flight PNH-REP, aft arrival REP partial day
2 more days SR
1 day car (or flight) to PNH, remainder of day PP
1 more day PP
flight PNH-BKK on TG or something reliable.

Alternate (Taiwan only as quick stop):
1 Day Arrival in TPE and overnight (unless early am arrival to connect to onward)
1 day flight TPE-PNH, onward flight PNH-REP, aft arrival REP partial day
3 more days SR
1 day car (or flight) to PNH, remainder of day PP
1 more day PP
2 days including car to/from Kampot & Kep back to PP (PNH)
flight PNH-BKK

I have tried to avoid that horribly pricey PG REP-BKK flight, which is why I front-loaded SR before PP. PNH-BKK flights are usually priced competitively. Also, due to lack of time, I wouldn't bother flying to Laos, N. Thailand, or anywhere else. Every time you change locations and particularly crossing international borders, figure that you gobble up a half day, and that 9 days melts before your eyes.

Daawgon

I would split it between Siem Reap/Angkor Wat and Luang Prabang. I've been to Luang Prabang before, and this is one beautiful tropical relaxing place. I'm coming again this year, and just before your trip (I'll be 5 days in Bangkok, 4 each in Vientaine and Luang Prabang, and 9 in Hanoi - starting Nov 14th). Vietnam is just too big to suggest it to you for a short trip, but Siem Reap and Luang Prabang would be good for short stays.

If you do get to Luang Prabang, don't miss the waterfalls - awesome!