Total ROI Calculation Help please

[Bob Gillar]

Prior to buying my first beach vacation (out of state) rental property, I wanted to use numbers and calculations to asssss my potential investment.  

I'm making an excel sheet with all the calculations found on this website (I will link at the bottom) such as ROI, Cash flow, etc.

I'm hoping someone can please help me with the data needed for TOTAL ROI. The article mentions taxes gained and lost - is this the place to factor in taxes paid on the income from the property (is that taxed at a rate of ordinary income?) - and is this where a deduction of mortgage rate interest is calculated or is that not necessarily a factor?

When factoring in the Equity Accrued; is this basically the equivalent of whatever portion was paid down from the principal of the loan?  Is theoretical appreciation of the propery used in this equation?   

As it's possible the article couldn't include every single item, are there any other items which a first time buyer should include in a TOTAL a calculation prior to the purchase?

Thank you! 

Link: https://www.biggerpockets.com/renewsblog/2010/06/3...