Well, I'm all caught up now.
I don't think what it's costing you is too outrageous considering all the work that is getting done. When I had to fix my parents house to put it on the market, I hired a contractor to fix the kitchen. My dad had built it on the slab of a back porch years ago. I had to take $32,000 out of my 401K to repair it. Every floor joist was rotted, the plumbing was shot, and when I ripped up the floor (which started the whole thing anyways) we were looking outside. The only thing holding a wall up was where the siding was sitting on cement.
If you don't mind me asking, is your mom helping you out on this any since she is coming to live with you. You don't have to answer if it sound too personal. I know quite a few parent(s) when they get elderly will sell their house and some belongings and come to live with the kids. Quite a few houses we have been through have what they call Mother-in-law Suites built on, or almost a whole other small house attached by a huge hallway.
One other question.....since it's your elderly mom coming to live, are you putting in larger doorways than normal, and if there is a hallway, is it wider than normal? The reason I ask is for possible wheelchair use down the road a ways.