Overall, I think she looks like a nice, useful mare, and she seems to have a rather agreeable personality in the videos, as well.
There does look to be something a bit funky going on in her croup and loin area, though. Without her stood up square, it is very difficult to say for certain, but it looks to me that her LS joint is placed behind the point of her hip (what would be called weak-coupled). I can't tell from the photo if she's got a bit of a hunter's bump going on or what, but there appears to be a dip on her rump between the point of her LS joint and her tailhead. Her croup also looks a bit flat-ish for a speed horse, but I am far from an expert on gaming horse conformation, so I'm mostly just flagging that as a potential issue, rather than actually saying it is an issue. Actually, scratch that; I'm far from an expert on horse conformation -- full stop. Just some thoughts on things you might want to take a closer look at if/when you go take a look at her.