It's not as bad as you might visualize.

An inspector may tell you what's wrong with a property on visual inspection of critical systems but won't tell you what needs to be improved to make a property marketable.It seems like a catch-22: how do i get the rehab costs before putting in an offer to get a bid on a rehab?

We went to the house and did a visual inspection as best we could without being able to get into the house. 

you are not listing the numbers in an order that would help you visualize the whole picture. you also have to have the numbers of the potential rent increase to see the opportunity as well.a quick look shows you that there is potential and it passes the 50% rule since the big 3 (piti) is less than 50% of the revenueuse JScott's spreadsheet and put the numbers in.https://www.biggerpockets.com/files/user/JasonScot...

What if there is a second mortgage)I'm not sure the legality of it but I would also drive by and do a visual inspection.  

Numbers first, visuals to verify.

We also found a duplex with a top floor partially renovated and move in ready, that contained a downstairs unit that needs a full cosmetic touch up, but should be move in ready in maybe 2 weeks time.I intend to visually inspect the neighborhoods and do several walkthroughs with an agent while down there next week.

It's the ambiguity of not knowing or being able to visualize that makes potential buyers turn away in most cases. 

I suggest you capture screenshots of any issues you discover and send them to the  email address for the BP support staff - support at biggerpockets.comAt least that way they can visualize what you found, and that is the first step to getting things fixed.

Not only are the visual externals shot.