If you want to stalk Snow White, here's a list of all the places she makes appearances. At the Magic Kingdom, you should be able to find Snow White at Cinderella's Royal Table, Dream Long With Mickey (the castle stage show), Celebrate A Dream Come True (day parade) and Main Street Electrical Parade (night parade). I am trying to remember if Snow White is still meeting and greeting by Cindy's Wising Well in the morning/early afternoon or if she was moved to Town Square.
At Epcot, she can appear at Akershus (princess dining location in Norway) and Germany.
At Hollywood Studios you might be able to stumble upon her at the Magic of Disney Animation building in the late afternoon/early evening hours. This is sporadic and not a regular meet and greet location for Snow so I would go with a grain of salt.
It is important to know that you are never guaranteed to see a specific princess at any dining locations. Although, you rarely see variation in what princesses are at each dining location, some princesses might just not be available. If you want to be extra safe, I wouldn't tell your DD that you will see Snow White at dinner and let it be a surprise.
Also, it is helpful to know that all Cast Members (including but not limited to Guest Relations) are equipped with the ability to dial a special number called the CHiP hotline where an operator can tell you where a specific character will be at a specific time. Some Cms can be clueless and not know what you're talking about when you request this (and I speak from experience

) but if you find a capable CM, they will be able to help you find any character.
Good luck, character hunting!