That version would be fine too.
As a side note, there are many national parks in the U.S. You would have to specify which one.
Lastly, picturesque is a very fine word, but a bit fancy for a casual conversation. The scenery was spectacular! The scenery was awesome. It's SO picturesque up there - I'm so glad I had my camera. But "the scenery was picuresque" falls a little flat in this kind of conversation.