However, due to very, very high cost of living in Silicon Valley, and difficulty buying a reasonably sized home, and given I will remain in Bay Area long term most likely (family all here), also need a property appreciation strategy to some extent, too.

But IF the interest rates were close, I'd certainly consider it, just to deploy all that extra cash on more buys.  

That’s an extra $2,700 a year we will make from that unit over the next year!

TIA for any guidance and considerations.  1)  I'm having difficulty finding a HELOC amortization calculator. 

Real estate investors are attracted to medium-term rentals to gain the benefits of extra cash flow versus long-term rentals while avoiding regulatory risks, high turnover, and intensive management of short-term rentals.While many investors are now turning to medium-term rentals to build their portfolios, the lending world has unfortunately been a little slow to keep up.

While I've definitely made more in appreciation than I have in cashflow, I don't mind knowing that my properties pay for themselves and I also don't mind the extra $5-15k every month. 

Your focus should be on avoiding loss, not earning extra.

“Because the $20,000 took so much away from their equity to put into another home, they decided not to sell,” she said.Another client of Chaname had difficulty selling his home because would-be buyers balked at paying $16,000 more for a home with HERO-financed air conditioning, duct work, water heater and insulation when similar homes were selling for less.The buyers argued they were paying for the improvements twice – through the higher valuation on the house and assumption of the loan.

I often wonder if the remote location (20 minutes up the mountain) is a turnoff and travelers are starting to prefer motel-like accommodations that are close to the main highways.Houses in the middle of the woods with no view, houses that are non-cabin style like they belong in a normal major city suburb, no game room, no deck to take in the view, no hot tub, no area for a fire pit, no room for extra activities like corn hole or throwing the football, poor driveway, steep entrance, tons of stairs etc.

And this is all assuming you pick just the right price that you don’t sell it for less than it’s worth or it lost it for too much and it sits on the market for an extra month or two.