I have never been to Timberline Knolls, but have been inpatient in a hospital setting for anorexia twice. My experience is very different than what a residential treatment would look like. I can tell you my story if you would like.
From what I gather, you would be with other women your age and older, the teens and younger are in a different program. That is what I gathered from their website. I am going to guess that meals will depend on the individual like they are in a hospital setting. Each individual has their own meal plan set up by the dietician.
If you haven't already, I would go and read up on Timberline Knolls, it seems like a good program, and they accept insurance. You could even call them and get information.
Again, I would be more than happy to share my hospital stories with you if you would like.