Below I have attached a spreadsheet of some numbers that I have put together showing the income from two investment properties with some money coming in from our own income to supplement saving for future investments. 

Some of the metrics that the survey provides and that I find valuable to understand are:- Population- Home Values- Household Incomes- Rental Vacancy Rate- Homeowner Vacancy Rate- Poverty Rate- Educational Attainment Rate (High School/GED & Bachelors)- Number of Housing Unit- Rent to Income Ratio- Rent to Price Ratio- Population on SNAPS (supplemental nutrition assistance program) percentage- Property Tax Rate- Median Age of Buildings- Number of Structures by Units (SFR, Duplex, Triplex, Quadplex, etc...)- Median Rents by Number of Bedrooms- Unemployment Rate- Employment Sectors PercentagesAlso take into consideration the direction in which each of these market indicators are trending.

I would also focus on making yearly goals of supplemental tasks which will help you reach your goal.

My wife and I are looking at a house in La Mesa and our goal would be to turn the 450 sq. ft. detached garage into a small studio in order to help supplement the mortgage payment.

The amount of useful information someone with even half a brain can learn here for free to supplement books from Amazon or even the public library is astonishing.

Obviously the present owner has 100% occupancy since he is supplementing his tenants rent. 

And then Notes.It’s all within the real estate industry, but different sectors that supplement each other.

I'm your age, but I'm single and my plan is to retire early and have the rental income supplement my pension. 

It's designed to interface smoothly with Excel and Google Sheets, allowing you to easily export data for further detailed analysis or to supplement your current model.Considering your proficiency in real estate financial modeling, your feedback on its functionality could be invaluable.

Theres so many different avenues to achieve your goal of supplementing your income with real estate.