Can we use BP Rental Calculator if we want to rent out our house?

[Sheila Salvador]

My husband and I are in our early 50's and we own a single family home in Hoffman Estates, Illinois. It is in a very good location because we are in the heart of Schaumburg area where it is highly develop. We don't have a lot saved in our Retirement considering that we migrated here in the U.S. so life was a challenge at the start. I believe that investing in Real Estate can help us with our retirement plans and I'm thankful to BP for the education that it provides. I have attended some webinars, read and listened to audio books and podcasts.  This is however my first post to get some valuable insights.

Here are my questions:

1.  How can I make use of the BP Rental Calculator in analyzing the profitability of renting out our house?  It seems easy to do it by "hand" by doing this math:  

Rental Income - ( Mortgage payment which includes taxes and home insurance + Repairs+ CAPEX+Vacancy+ Others ) = Cash Flow

I am not buying the property so I'm a bit confused on where or how do I plug in the numbers above or if we have the house refinanced, do I still use the "rental calculator?"

2.  Is it better to have the house rented out first and wait for the market to pick up and sell it?

3.  Here are the "numbers" pertinent to our house :

    Mortgage Payment = $1,379 ( including taxes and insurance ; Mortgage balance $138K out of the original loan of $165K ; 22 more years; 3.875% ; 

   House built on 1956 in very good condition; new roof with solar panels; 3 BR 2 Bath with 2 additional rooms as office and family room; 1450 sq ft.; 

  Average rent per Zillow is $1950 but our neighbor rents same size house as ours for $2300 and our house has more "features" than hers.

4.  Since we want to invest in small multi-family preferably side-by-side town-homes or condos and have the other units rented out, how do I prepare for this plan?

Would need some inputs especially on how to analyze the numbers therefore, if I can get some guidance on how I can develop this skill in this specific areas of interests, would greatly appreciate it.