Hi Adam, 

I'm glad to hear that you've decided to spend your holiday in Vietnam. So, I'd like to recommand  you a wonderful place in my country.  Da Lat is the deal one which is in Lam Dong Province. 

First of all, it is attracted by many visitors because of its beatiful landscapes and cool climate. You can visit many places in this city such as: Valleys Love, Da Lat Market, Datanla Waterfall, ....etc. For me, I like visiting Da Lat Market where I can eat many typical food and go shopping. You can not only see many beautiful landscapes but you can also relax and enjoy the fresh air. This is the first time you've been there so I think you should visit Da Lat Flower Garden. Despite its cold temperatures, the flowers still live very well. You can have flower watching and take lots of photos with this peaceful place. 

In short, why don't you try to visit Da Lat ? It's an interesting place, isn't it ?

Good Luck !!