Since a 4-plex is typically a two-story, the surface area is a bit less than a 3-plex, which is often an L-shaped sprauled out structure.I have some ideas for you in terms of how I’d structure this your deal to gain the most out of it – too long for this post.

This barely scratches the surface, but hopefully it puts you on the right track.

I don't expect problems here.Plumbing--Also don't expect problems here.Elevator--No experience, so will get this checked.Landscape/irrigation/parking ingress/egress issuesGlass and exterior facadesAll interior surfaces and fixturesSecurity issuesInternet/phone access Examine all suites, common areas, and service areas, all I can see, smell, touch, etc.Anything else on physical due diligence?

Might be a value add in the rehab when the jobs surface.

During the rehab they were able to vent the heat to adjoining down stairs rooms through the ceilings.

Just like anything else do your due diligence on multiple lenders and retrieve what they have to offer before running your credit.I'm not sure if I even scratched the surface but I hope this helps a little.Just my two pesos. 

Maybe it is work you are actually doing or you are hiring out but either way the same couple things end up more than they really should be.For instance, you can predict carpet costs well but half the time the tile guy runs over due to discovering extra surface prep is required.

Providence on the other hand offers a little better ROI due to extremely low prices, but is known to be not tax friendly and, on the surface, doesn't seem to have much growth potential.  

 Just after any feedback on a property i came across called Property Tracker Pro.What the product does ;●Tracks properties adjacent to the investors property (monitors properties on three boundaries)●Notifies the investor when any of the adjoining properties are sellingFor the investor, this product gives them the opportunity to acquire a “double block” for increased resale values or development opportunities.The cost of Property Tracker Pro is $84 ($AUD). http://propertytrackerpro.comHas anyone used this product before?

there are a lot more but that is just scratching the surface.