I have been in Vietnam once (Hanoi capital) for business, next month my family and I will come to Vietnam for holidays for 10 days . Vietnam is a beautiful country so I recommend you to come there.
If you are interested in heritages of Vietnam you can visite Hoian, Thang Long Citadel, Catru,…these are heritages of Vietnam.
I have never booked any tour with any agent but fortunately, my friends have. They told me about their one-week vacation with a company named Vietnam Heritage Travel. They were very satisfactory because this agent had a reasonable price with very good services.