Question is: what will produce the best return in the next 10 to 20 years? 

I have a proof of concept web page and can provide a personal story and touch.

That is what it is all about.It sounds like your property is quite the income producing piece of real estate with multiple income sources.

But, they are structurally separate and both income-producing.

I definitely recommend that you seek out a Certified Cost Segregation Professional so that you are confident in the quality of the work performed and the deliverables produced.

Since then, she has sent the keys as agreed but hasn't produced the payment as she promised.  

It appears they've remotely shut down the panels as they haven't been producing for the last month. 

The problem: The thought of working 5 more years in a high stress, anxiety producing W2 is almost unbearable.

After the home is rehabbed, rented, and producing month-after-month cash flow, the initial lender refinances the home into a fixed-rate, long-term mortgage using his or her great credit, but both remain on the legal title for the property.

How have the property been producing since you closed in 2020?