Now, the house that is about to refinance, I am thinking of turning into a MTR for traveling nurses, or other professionals as such.

That's exorbitant in my area for a house that size.

We had to bring the 1925 house to 2023 code which involved un-installing 26 windows that were already nicely installed (in appearance) in the house, reframing them to 2023 standards (at the time) which also involved strapping the bottom of the wood framing with metal straps (mind you this all after we had already completed the inside renovation).  

A house that's similar, but 10% larger than another usually isn't worth 10% more.

I have a lake house near a University.

It’s like a scene out of a zombie movie as these people stagger down the middle of the street to the liquor store on the corner past my house.

Working with the city to find a solution.There is a similar situation near me where an investor bought a short term rental house, rehabbed it, ran it for a while, and then got in trouble with the town after a neighbor complained and the town said short term rentals weren't allowed in the community. 

I've always been interested in finance but housing had always been a rather boring investment.

This is the heart of the reason housing isn't mroe affordable, that landlords bear these types of costs every day.You could probably find cheaper labor, especially to haul away the junk, but not easily as an out of state investor. 

You can also start exploring a house hack to utilize the lower DP