Maintaining a second home is very likely a money loser. The fact that you didn't even bother to lay out a plan for generating vacation rental income indicates you haven't thought through the full range of perpetual costs.
State tax authorities are generally very good at sluicing out cases of people superficially changing residences to avoid taxes. Don't do it unless you're really going to change residences across state lines. Schools, clubs, associates, doctors, dentist, vehicle registration ... everything needs to be in the new state.
Your entire proposal as described here is very one sided. Your list of cons needs to be fleshed out more, you need to think through it more and come up with something much more balanced. You've already convinced yourself that it's a good idea, now convince yourself that it's a bad idea. If you can do both, and the pros still outweigh the cons then it might be ok, however...
You're talking about building this as a potential retirement home, and selling your current place down the road, but your wife doesn't even want to move to TN. You're getting ahead of yourself, slow down a bit. Making big plans independent of your wife is only going to cause marital strife. Not sure about your wife, but mine can detect from a mile away when I'm trying to drive my own agenda rather than really listening and having honest discussion.
My recommendation: Deconflate the desire for a building project, a second home, and a retirement home and treat these as separate issues. If you want a project home, then find something close to home and treat it as a side hustle, with a clear business plan for how you'll make profit. Build/remodel, then sell. IMO, a second home is a money loser, almost never a good idea. As for a retirement home, sounds like you and your wife need to have a lot more discussion about your long term plans, which may mean finding some compromise or maybe even you allowing your wife to carry the argument to stay put.