If you can rent it for enough to cover the principal, interest, taxes and insurance and still put money in your pocket, plus cash flow on the property you're purchasing, that would be ideal.

I've rented rooms to BSSM students, but I'm not sure that I want to continue with that group, or switch to independent senior living, etc. 

You can look on websites like https://www.corporatehousingbyowner.com/search/United-States... and https://www.furnishedfinder.com to see what similar houses are rented for.

The investment city determines rent growth rate, appreciation, and income longevity.What determines rent growth?

Quote from @Marcus Ball: After struggling with local rehab properties in California, I switched to build-to-rent developers and chose a 1031 exchange.

Your rental pool is higher renting out at $1000.  

and I also rent to voucher holders in the Milwaukee market. 

It seems like location would be especially critical with pad-split (and similar systems), but I’d love to hear your thoughts on what to watch out for in terms of zoning, safety, or demand.Also, I’ve traditionally rented out units the regular way, so I’m curious how screening tenants works for you with the pad-split (and similar) model.

With $1mm cash we can do 3 locations netting $40,000 before income tax per month.  

You want the best location for making money.