Well, you DEFINITELY need to assess her rotation and you DEFINITELY need a good farrier/trimmer and vet on board. And then add about 25% to the recovery time, 50% to the cost, and 100% to the time invested in care and you have a place to start from. Just to be ultra conservative. That is assuming that the farrier and vet think she has a future as a riding horse.
You can ask about her training, but take all answers with a huge grain of salt. If they have videos of her being ridden, you could look at those.
Good luck and let us know what happens.