How to use Rental Calc on Turnkey Properties

[Casey Burnett]

Wife and I are looking at properties near my parents in another state.  Through BP we've talked with some very helpful people.  One is with a Turnkey property sales and management group.   Now I'm trying to complete due-diligence by running numbers in BP calculator.

My basic assumption is that I must consider the premium on a rental property above zillow's estimate price as the "rehab" cost in the Rental Property Calculator.   This does a few things: 

• how much of a loan I can seek 
• how much cash I really need up front
• It would more accurately reflect any appreciation (though I'm planning on being a buy and hold investor, and equity is less critical than positive cashflow, IMHO)
  

Example:

Turnkey(TK): Asking price: $35000,  with tenant $650/mo.
TK: $300 setup cost

Zestimate:  $18500

Closing Cost: $1000

In BP's Rental Property Calc I then would put that the 

• rehab cost would be $16800  (16500 premium + $300 setup)
• the value after $18500
  

So,  what have I missed?  Does this make sense as a way to use the Rental Calculator for analysis of turnkey property?