I assume that finding a good PM and making efficient improvements can be challenging.

Any advice on how to invest my money in real estate while being the most efficient?

This is akin to stating the obvious, as DSCR assessments are fundamental in determining the viability of such loans, similar to DTI (Debt-to-Income) ratios for residential mortgages.Your emphasis on the operational efficiency of well-run assisted living facilities highlights that their financial performance typically isn't constrained by DSCR limitations.

I know I can probably house hack my way to 5 properties in 5 years, but I assume I'll probably learn more efficient and aggressive ways to scoop up more properties as I complete my 2nd-3rd house hack, so that I can start picking up more than 1 property per year.I don't want properties that will take a lot to fix up, I'm fine with cosmetics and do-it-yourself type things.

SchenectadyThere are colleges, hospitals, and other workplaces in the area as well.

One of my strategies will be to put money into energy efficiency to decrease heating costs, and increase my cash flow - Maine has some good loan programs/rebates that can really help tighten up a building, and finance efficient heating, so I'll be taking advantage of those.

Aside from zoning issues, permits, and city/county requirements, which are highly variable, I'd like to get an idea of how many units/buildings and how to lay it out for most efficient use of space for those 2 acres.

Your reply seems well thought out but I hold the belief that the free market is more efficient than a market being meddle with.  

A/C window units are getting better, cheaper, and more efficient all the time.

Effective remote management hinges on strong organization, reliable local contacts, and leveraging technology for efficient communication and oversight.