Originally Posted by
richardinmotion
Visa on arrival (VOA) is permitted for one of the following purposes:
Visit Vietnam on tours organized by Vietnamese international travel agencies;
Technically:
If you apply for the VOA approval letter, you do it through a travel agency approved to give those letters. Thus you are on a trip organized by a VN travel agency, no matter where you're going or what you're doing.
Realistically:
Apply for the letter; you will be let in if you bring it and the $$$.