They understand this backwards and forwards.

Knowing the rent, you work backwards to a purchase price.

If he can identify a number then work backward from there to come up with your offer price and terms.

Exactly start at PM and work backwards..

But if you're looking at it properly, the backward dated views are almost irrelevant to the future of what real estate will be forced to do.

I will let you know most multi family properties being sold in todays market are doing things backwards in terms of condition and tenancy. 

The value of the lot is what a developer is willing to pay which they work backwards from resale potential.

And if there is a conflict the court system will bend over backwards for a dead beat tenant or squatter and hold landlords to a entirely different standard. 

why no MLS  agents may have done a bunch of your homework up front.. just offer what makes sense to you.. me personally I would start with  the zoning maps and only look at props zoned for the size you want to create.. then work backwards.. no sense chasing deals without knowing the zoning up front.

I would say first step if figuring what kind of goals you're looking for, and then going backwards from there.