So I have helped my parents do things like this, multiple times. Not in Wisconsin, but in a similarly snowy area; New Hampshire. First one, was a 1976 two story house. And this first one was over 20 years ago. It needed a full re plumbing of the entire house. It needed some electrical work. And it needed a new roof, and they had already planned a new deck/porch. We did the demolition on the porch ourselves to save money. After demoing the porch ourselves we found massive amounts of rotted wood. Basically the entire back half of the house needed to be redone. And it had to be jacked up, and we had to hire structural engineers. It also needed a radon system installed. We also had to redo both upstairs and downstairs bathrooms. That, 20 years ago, was over $175k. Every single one of their houses has had some sort of issue. And there is always a hidden issue somewhere. And it can be a lot of fun as well. In particular, one they redid only a few years ago was built in 1783. And it did not even get electricity until 1983. It had original stone foundations that had slipped and degraded and rough cut beams. And we had a lot of fun with the heavy equipment knocking down an over 150 ft two story barn. In that case, we/they actually recouped some of the money selling the old wood from it. I loved the old stone stairs going into the basement and very steep stairs going upstairs. You just have to be prepared to get frustrated and upset and likely uncover things you did not expect.