@Matt Gee, the numbers look best to me if you decide to SELL it straight away for its full ARV after you do the R (but, try to get it for LESS than $120k in the first place)?

It takes KNOWLEDGE, money, marketing, negotiating, and system structure.  

Thanks - Randy & Linda R

He designs heating & cooling systems for mostly commercial buildings.

If a company knows that you are a real estate company (using your NAICS or SIC code), they will shy away from that.There is someone named Jorge Bueno that has a system called "The Business Codex." 

I agree with @Frank R., sell the shorter lease to her as wanted mutual protection.

Building looks to be in OK shape, but there's no capacity to expand the septic system beyond the one bathroom, we're told.

Mark,If you are used to and have the infrastructure (people and systems) and the guts to handle C-D properties, then by all means get the deal as this sounds like an awesome opportunity.I was able to get 2 buildings - a 36-unit and a 24-unit with no money down - exactly taking over the mortgage payments of the seller.

Marcia also gave you some good advice if you're convinced on using floating system.

As of now, I am only slightly interested in the Allison unit but even that's questionable because of what Steve R. mentioned.