Our 6yo DD was not crazy about the scary rides. I honestly thought she'd be fine on everything but Space Mountain & Indiana Jones this year, but after going on the rides, I realized there were some that were a LOT scarier than I remembered them being!
She rode Splash Mountain, but didn't like it and didn't want to go on it again. I thought "oh its just one big drop and its over in 5 seconds, she'll be fine". But I had forgotten about the two dips and the dark part that are before the HUGE drop. She was not happy about that and was crying by the time we got off!

I felt so bad!
After that we were a little more cautious about what we took her on. She went on Thunder Mountain, as again, I didn't remember it being very scary...but it is a LOT faster than you think and she didn't want to go on it again after that.
She didn't want to go on the Matterhorn just by looking at it (and after riding it myself, I'm glad we didn't make her, its scarier than I remembered it being, too! Its almost all in darkness and super fast.)
She did go on The Haunted Mansion, but it was the Nightmare Before Christmas overlay so it wasn't as scary in my opinion. She enjoyed that one a lot! I wouldn't have taken her on it if it had been the normal version though.
She liked POTC, although she was a little jumpy during some parts. She rode it three times though!
Other than that she went on everything else and enjoyed them.
A must see for a 6yo girl is DEFINITELY the Princess Fantasy Faire. Its about an hour wait, but worth it in my opinion. Get there early one morning (like before 10am) and you won't have to wait as long. You get to have a meet n greet and pictures w/ 3 different princesses (they switch them every 30 minutes or so). They also have a beauty parlour where you can get their hair done for about $40 or face painting/makeup for about $10. (We did the face painting, but honestly, I think it would be worth getting her hair done if its in the budget. I saw a few little girls during our stay and their style lasted 2-3 days.) If you do it, do it before standing in line so its in her pictures w/ the princesses. Then after you meet the princesses there is a princess show down in the auditorium where a princess teaches you to dance and curtsy, etc, DIY crowns, and also story telling by a princess every hour or so. All of that is free! Its nice b/c its all in the shade, there is a lot of seating and you dont have to go anywhere, just chill and watch her have fun. There's also a bathroom and food stand right there, so you can buy lunch, too. You can easily spend 3 hours over there one morning and have lots to see and do.