Originally Posted by cheltzel

From reading this thread it looks like we will get the Fast Track vouchers since we are arriving in TG F. Is that correct?

Better than that! You'll get a buggy service that will take you from the gate to the lounge, or immigration (if you are going to HKT some other day)

And on departure, we will be checking our bags through to HKG at HKT. I assume that we will go through the passport check in HKT and just do a normal transfer at BKK. Again, is that a good assumption?

Yep, you'll get a sticker (that easily falls off) to put on your shirt to identify yourself upon arriving at BKK. You won't have to go through immigration again, not even carry-on baggage screening! I guess someone else will have to answer you about the buggy service, don't have that experience of domestic C/F -> Intl F.