Hello, if it's not a secret, how long have your parents been together? I'm sure they have a very strong love, may it last for many more years. Would you share your thoughts on what surprises you mentioned? I think One Nation Travel can handle this task. I read about them in an article from GetExperience
https://blog.getexperience.com/news/top-us-travel-agencies/ and then used their services when I was helping my brother organize his honeymoon. They wanted to visit not only France but also Italy, and they even managed to save a little money.