We leave for our APT trip in three weeks. Starting in Hanoi then Halong Bay, Hue, Saigon. Board a Mekong cruise then Siem Reap and all points between! In the cities we are in 5* hotels then Mekong Serenity. I have absolutely NO idea what to take for evening wear. I don’t want to be under or overdressed!   Those of you (ladies) who have done similar trips, please advise me.   Thank you!