The MTR and STR would be more for travel nurses, corporate professionals instead of people vacationing.

The reality is ADUs, casitas, mother-in-law suites, etc have existed for decades, much longer than the fairly recent state level ADU laws some of which are already 5 years old.  

Usually, "family" is considered the first tier, mother, father, sister, brother, daughter, son, your spouse, grandparents, all being in a direct linage, blood or marriage, your great uncle by marriage isn't in this group. 

you can also list on a travelers fb page for your area, like boston travel nurses page.

Originally, I lived in the main portion of this house and rented the mother-in-law suite (primary bedroom) separately on Airbnb.

Maybe 6 or more months ago David Greene had someone on the BP podcast talking about mid-term rentals for travelling nurses and that's exactly what they did.

However some of my best months are in the winter; we have visiting families for SU students, a ton of traveling nurses, and we are about to have the biggest chip manufacturing plant in the country. 

This is a big negative for me from ever wanting to do a MTR.There may be exceptions to this if your property is in a high demand area like a large hospital where there are many traveling nurses.

A single-family home is a single-family home for the town, not a mother-daughter situation.

The population has been growing here year over year over the last decade, it is home to The Ohio State University which has over 50,000 students that live here along with those that visit, and it also holds a diverse range of young professionals and traveling nurses to fill the demand of the multiple business corporations and hospitals stationed here.