Compare this to selling the Market A property in year 3 which has appreciated 5% a year and is now worth $550,000.00.

It just makes life easier - they shop a variety of insurers and are more easily able to compare apples to apples because they know how the various companies present coverages.

There will always be demand in the market (it's not like some covid markets that could disappear as vacation destinations almost entirely over the next decade), and the regulation risk is as near to zero as you can get in this industry so long as you buy in the approved tourist zones (again, compared to some smaller/less mature markets where they could outlaw STRs tomorrow).For short period cash flow there are better options. 

Electric heating compared to gas heating is much more expensive, so if the tenant is going to use it, definitely have them pay for it.

I hope the comparative market analysis I just sent over view email helps.

While Reonomy is not comparable as it's for commercial properties, Propstream is. 

But there are also some real challenges, like dealing with lower tenant quality on average, the extra red tape, annual inspections, and the longer time it takes to get tenants placed compared to the open market.

Compare that to a business/company.

Ironically, platforms designed for real estate (Zillow, Apartments.com, Rentler, etc.) produce very few tenants for me, compared to FB Marketplace (and I also find a lot of their functionality to be user un-friendly, from the landlord side). ...you'd think that platforms custom-made for real estate would make the process a snap for landlords, but it takes me a lot longer to post and manage rental listings on Zillow or Rentler than it did on Craigslist.

A HELOC gives you flexibility since you can draw as needed and only pay interest on the amount you use, which might be useful if you’re not sure exactly how much you’ll need upfront.That said, it’s important to compare the interest rates between a HELOC and your expected returns in the stock market—if you’re making more in your investments than you’d pay in interest, it could be a good play.