I was born and raised in Louisville, on the southwest side of town. Bought the house I was raised in from my parents. Thought it would be a good place to raise my kids. We moved to southern Indiana in 91 when our kids were small. I can't say for sure, but I'm guessing that the taxes in KY/IN are much lower than what you're used to paying in NY. This area is the only area I've ever lived in, so take my opinion for what it's worth. Bottom line has me thinking the difference between IN and KY is nil, tax wise. One state is higher on some taxes, but less on others, so it's a wash.
You state that the two of you are very conservative.....politically? Louisville, which is Jefferson County, is the most liberal leaning county in the state. The rest of the state is fairly conservative.
What part of town would her employer be located? Asking because of the various commutes from different areas.
Gun laws are similer in Ky and Indiana. Ky is an open carry state. Concealed carry is, I believe, 60 bucks or so for 4 years. Initially, you have to take a class.
Indiana has a lifetime carry license for 100 bucks
both are NFA friendly states.
If you are into deer hunting, Indiana doesn't let you use most rifles, Ky does.
I can try to answer any specific Q's you might have if you want to IM or email them.
EDIT.....lots of boating opportunities in the area.