My conclusion is that the Vertex42 spreadsheet is just fine and it was very easy to simulate the situation. 

@Nate O.To spark your son's interest in real estate, begin by teaching him financial basics and slowly introduce real estate concepts through hands-on experiences like simulations, shadowing, or DIY projects.

I have many years of construction experience and have also done a fix and flip, in addition to ground up construction, as well as 10 years of entrepreneurial experience running a paddle board rental company, and advancing science through developing theoretical methods for efficient large scale simulations...I guess my problem is I can't seem to figure out how to find the money to do more projects, which is why I've been trying to sell my house.

Until then working through simulations until we happen upon a deal that works for us.

They usually have simulators that will tell you how much you need to pay off on a particular debt to accomplish a particular point gain on your credit rating. 

*Lake Anna, Reston Virginia*Originating in 1990, The Reston Town Center is a major employment and entertainment hub in the area, with companies such as Google, Leidos, Facebook, Microsoft, General Dynamics, and Fannie Mae, to name a few, more than 50 retailers, including an 11 screen LOOK Dine-In Cinema, CitySwing (Golf Simulator), a seasonal ice rink, many well-renowned restaurants and bars, and other highly attractive amenities such as a full service 243 bed hospital, a new metro, and the Dulles International Airport that is receiving $700 million renovations by 2026*Reston Town Center*Source: Rediscovering Reston-- the First Planned Community in the USSource: Washington Dulles International Airport to Expand Passenger and Cargo OperationsOne of the biggest points of discussion over the last few years has been around the office market, and how the rising office vacancies due to the shift towards a work-from-home and hybrid work schedule have pushed many companies to downsize or relocate out of previously major employment centers.

I suppose the mathematical formulation of an approximate quantum dynamics algorithm for the simulation of large scale molecular systems, which has been used and cited by people all over the world, including a research group at Cambridge may fit the definition of renound... 

@Robert Rixer, I don't know how creative these are, as many are common plays:Valet TrashFencing in first floor yardsProviding washer and dryers for added rentReserved, Covered parkingTech PackagesInternet and Cable contracts, with reimbursementsPayment Plan rents, with small service charge (i.e. bill 1/4 rent each week)Reserved Rental cabanas at poolPrivate pool party rental optionGolf Simulator in clubhouse - fee basedOn site, self serve car wash (quarter feeder style)Charged group fitness/personal training servicesGame room in clubhouse with monthly subscription for tenants (Xbox, Playstation, etc)Changing out high maintenance grass for astro turf or lower maintenance/lower water use shrubberyBut ultimately, I think a lot of NOI increases come from deep dive into understanding EVERY expense and finding ways to minimize them, and/or no outsource them.Train maintenance team on basic HVAC and appliance repairs (find way to get them licensed as needed)Buy paint sprayers for faster, easier turns versus having to hire a contract painter, and possibly repaint whole unit each timeStandardize all finishes, so you can buy in bulk, everything from hinges and door knobs to cabinets, paint colors, and light fixtures.Potentially get leasing people onto lower base salary with higher bonus potentialBulk/bundled insurance across portfolio (even better at scale is to self insure)Regularly test sprinkler systems for leaks.Non-NOI, but benefit to you: partner with insurance agency to get referral kickbacks from your tenant base for renter insurance.  

I feel like too many treat this sort of question like it is a simulation or a spreadsheet.

I think I have a decent grasp on how to calculate all the expenses and simulating potential gross income, including potential cash flow.