I was told by a friend that his dad who runs an appliance business has "keys to every type of washer/dryer coin box".

Another thing, the threads move down the forums rather quickly because it's so busy, so the odds of your post being seen for long by very many people is minimal. 

I'll use these next 20+ years to not only evaluate Real Estate, but other income sources (businesses) to see if I can find something.

Cost of doing business.

But it is my opinion you should try Airbnb, VRBO, booking.com and FlipKey and give it a chance to see if it is adding business.

If you're going to reinvest the proceeds you might want to consider a 1031 exchange or a cash out refi to generate the investment funds you desire for your next project.

Some investors also use a business line of credit backed by their cash flow, which can help with future deals.If you’re planning to scale, maybe start stacking that cash for the next property or even park some in T-bills for short-term returns.

Flipping is a production business.

It's a place to legally go and sell stock/business without capital gains.

Every day is a school day in this business.