Sienna was C-3PO for our Stars Wars Droids family Halloween costume. But if you asked her, she was "the Golden Guy", or if pressed to name him, C-Creepy-O. Sooo, I made her a different costume to wear to school. And also as an excuse to make her a Rapunzel dress-up.
Peasant dress pattern: Simplicity 2377 (Minnie Mouse dress)
I made the dress much longer than the Minnie Mouse dress, and in a bigger size, but it's pretty much the same. The light purple pattern has hearts traced all over it, a cute little detail.
As for the hair, I estimate the yarn cuts to be about 9 feet long. I'm guessing you'd need 12 feet strands to make a floor length one. Sienna is about 44 inches tall. It's a lot of yarn.
She loved wearing it for Halloween, and she loves dressing up in it after school most days. Bonus: It was probably less than $5 to make. And it's the same yarn I used for the C-3PO hat.