And the list goes on......If I were to estimate the time I spend in this business is likely 70% on acquisitions, 15% on marketing for investors and 15% on managing current inventory. 

The numbers below reflect my best estimate WITHOUT bridge loan paydown. 

From estimates received from contractors it might be a maximum budget of $30K to do a garage conversion where I'll rent it out as a 1bd/1ba for about $700 monthly or make it into an AirBnB that can average $2k a month.OR use the 30K to use as a downpayment on a new property with a mortgage but I feel the profits would be less in this market along with the rising interest rates.

And I think there is a real chance that interest rates AND inflation kick in over the next 5-10 years. 

I estimated 123,000 in renovation costs, purchase at 81k.

Will asking property managers directly about the rents/expenses for a particular property be the best way to get an accurate estimate? 

The calculator made me estimate my repair budget, but even if that number holds over the long run, I have no idea whether I spend more of it up front or later on, and if I keep that money in an interest-bearing account, that will impact how much it grows.The calculator is a great starting point, but like any tool, you need to understand how to use it.

The 300k ARV estimate seems optimistic as well. 

Next stop is your city zoning office.That it already has a meter bodes well for your chances.

Houston might offer the best chance.