Bigger Pockets (BP) has an STR calculator Excel document. 

Plus all you need is 1 error, a circular reference, or simple mistake in the excel template to lose credibility.

I have compiled many of them from target areas into excel with owners info, address, ect.

What I'm hoping for is an Excel or spreadsheet template that allows me to play around with these variables and, most importantly, calculates the IRR and TIR for each scenario.Does anyone have a board or Excel sheet they use for this kind of investment simulation?

Quote from @Collin Hays: I got a chance to read this over lunch today, and it really hit home some excellent points about investing in real estate. 

There are some great neighborhoods here that balance cash flow and appreciation, like Fountain Square and Bates-Hendricks, and parts of Irvington.

is there any cash flow?

If you sit on the sidelines waiting for the unicorn, you’ll miss out on multiple strong investment opportunities that provide excellent long-term returns.Instead of chasing perfection, investors should focus on leveraging assumable loans in one of two ways.Two Strategies for Winning with Assumable MortgagesAn assumable mortgage gives you two clear paths to success.

Purchase price: $142,000 Cash invested: $12,500 We were able to RTO this home at a purchase price of $184,000 at a monthly rate of $1,850.

If you paid all cash, you paid full price for the property, and the cash flow, any amount of cash flow, is only playing catchup.