This post is in response to the Anon who asked about the M'Doidoi doll located at 6015, 10531.
The best way that my friends and I have found to reach this particular doll is quite an interesting pathway. It may take you a few tries to get there, but it does work! There's no race-specific things involved, just jumping and falling and the like.
Our starting point is on the south side of Cassana Estate -
The puzzle is also located in this area, about 5886, 10719. Oddly enough, I found there is a M'Doidoi doll located right beside the puzzle. I'm not sure if it is collectible or not, but it's worth checking out. Might get you an easy way out. ;-)
If you do choose to follow through with this, follow the pathway that I marked with a red line on the picture above till you reach the tower that blocks your path. Down to the right there is a roof.
Back up about 10 or so paces and, while mounted, you should jump down onto that roof. Once down there go to the other side and look down to your right again. There is a round pillar that you should slide down onto. Aim carefully though, you may slide right off.
Once you're on that pillar, jump to the curved edge of the roof that surrounds the tower straight across from you. Make your way around it and to the tower on the other side and there's your doll!
I hope this helps you! Sorry it's somewhat complicated. If anyone finds an easier way, please let me know!