Last night, we bought a treadmill for Abby. We have been looking for one that we can prop the back up, so that it mimics walking downhill. Most new ones will stop if they are not lying flat, so we found an old one for $60 at a used sporting goods store. Yay!
Since she's still unsteady, I am just having her walk for a few minutes on it a few times a day. When she starts walking like she used to (which she will soon, hopefully), we will try walking downhill. We are having her practice the movement of walking down steps by walking downhill on a treadmill. At the conference, a presenter said that walking on a treadmill showed the same results as a session of physical therapy in a study they did with girls with Rett. Abby doesn't mind it, especially if she can watch a video while she walks. While we will always support her at her waist her arms, I do want to make something to go in front of her to hold on to. Maybe I can tie something to the handles, which are way too far apart for her to reach right now.
It does seem funny that she is the one person in the house that we want to gain weight, and she is walking on the treadmill.