sounds like you are expounding on this    http://www.ccim.com/cire-magazine/articles/323227/2013/09/cap-rate-calculations-todayReasonable when market caps (sales) are not available but not a good substitute when they are.

Substitute either City Hall if in Boston, or Tax assessor's office. 

Substitute duplex for triplex or four-plex, whatever floats your boat.

There is no substitute for personally meeting the people who will be the core of your investment team.

I will say that substitution of notes is a very difficult thing to do, similar and at the option of another is fine if accepted, but it's not the same investment, risk, maturity, the UBP won't be the same but that can be adjusted, credit standing and likelihood of refinancing may not be the same (a note paid off early increases the yield of a discounted note).

And this supports the point that online forums such as BP have their place but are no substitute for doing your own legal research.

In that note is a substitution of collateral clause that allows me, at my discretion, to move the note to another property.

I don't think EM is a substitute for POF.

No matter what a mentor tells you, there's no substitute for doing one and learning.

RECENTLY SOLD COMP data is the key, but you need to know how to use that data correctly as it relates to a subject property.Alas, sometimes there is no substitute for experience!