I prefer reading books and information via audio (such as podcast) and visuals helps a lot. 

I'm looking into a 4plex to buy but other than asking the owner a lot of questions what's the best way to go about visually inspecting the building since its full of tenants?

I thought this thread was good already... now it's about to go HNL. edit: visual aid

I'm more of a visual person, so clicking on the map and looking at the concentration of colors in different areas has been helpful.

I keep a notebook as this is a visual reminder to take action.This list is ONLY of those things that i "CAN" physically do today.

You can also import into qgis, it's easy to learn, and draw geofences around the area you are interested in, then export to xls and mailmerge for your postcards.This way you own the list and do not have to pay per use, ie it is not seeded, and you can also see a lot patterns visually, ie hotspots, etc if you use a gis app. 

Of course you won't be able to check for functionality, but the visual condition should give some clues.  

I'm looking for visual reference material that would provide an at-a-glance display of at least the essential puzzle pieces to a real estate transaction specifically concerning the entities/parties involved & their role.

If you have a forced air system, rooms (be they closets or a small room - but generally speaking an area with a door) and there is no supply in it, they can get quite cool - even if the bedroom is comfortable.Before poking holes in walls (which is all you really need to do, just drill a 3/4" hole and inspect... visually or by sticking your finger in it... very easy to fill/patch), I'd check to be sure that the area above and below were insulated if they are attic/crawlspace/unheated basement.If it's not insulated, you could remove the drywall and install insulation or you could use loose fill using a series of larger holes - just be aware that horizontal bridging will require two sets of holes for each stud cavity.As for installing cedar... depends on type and thickness, but I prefer having a substrate regardless.

That way I can really learn and understand the root of what they mean, and it is visually nice to see as I learn.My only critique is not easily knowing what cells to input, versus what ones calculate.