After analyzing the potential ROI, we negotiated a fair price of $58,500, ensuring room for renovation costs and profit.

83k profit Lessons learned?

To get things done as quick as possible , charging by the hour cost the contractor money , charging by the push/inch  is the most profitable way to do snow . 

I have a question and would really appreciate your input.I’ve done a couple of fix-and-flip projects in the past using hard money lenders, but I’ve noticed that their fees and interest rates significantly cut into my profits.

Additionally, keep in mind if you do this in a Roth then there are NO taxes on the appreciation, rental income or profits when the Roth liquidates the asset. 

small portion" of profit is not worth the possible legal issues.

Like @Kyle Mccaw noted there is significant value in goodwill and I imagine you profited nicely over this pleasant long term relationship. 

But that also depends on your down payment- putting only around 20-25% down is hard to have a profitable STVR.Ultimately with STR v LTR, I'd be mainly curious about your intended use of the property. 

The $10,000 yearly maintenance fee is really hurting your cash flow, as it’s eating up all your profits.

Make it a habit—underwrite one deal a day until you get the hang of it.The tougher part, and I think what you’re really asking, is how to turn solid underwriting into a profitable deal.