I am currently stockpiling cash, lowering my liabilities and being patient.

Why would anyone voluntarily want to live someplace where they need stockpiled food and water to survive and weapons to stave off the looters?

We also hoped that this would help us grow our cash stockpile quicker so that we could eventually purchase more rentals.Lesson #2: Be smart but get in the game.

My wife does consulting where she will co-host for a percentage of the hosts earnings but we use that money to stockpile furniture for future projects.At this point in time Airbnb is actually keeping people being backed by LLC's/Corporations out of co-hosting by not allowing you to be working under a company so your payout method will go directly to you and not to an LLC.

They are "stockpiled" and can be used in future years when you might be eligible to take them, and will be used to reduce your capital gains when you sell the property down the road.

You may not have repairs now but surely you'll have repairs as tenant turnovers and you'll want some money stockpiled in case that furnace goes out in February or the Dryer stops working etc etc. 

Paying down a mortgage is stockpiling cash, actually closer to hoarding cash. 

Right now, I would characterize myself in the accumulation phase, as I am essentially stock piling cash to be able to put down the down payment and have plenty left over to account for any unforeseen expenses (repairs, vacancy, etc.).My question is, where should I be keeping this cash?

I keep a fair large cash account, though it's unsettling to keep a stockpile of cash that isn't growing while waiting for the buy opportunity.Are there other strategies you know of for mitigating this risk?

Once you are comfortable with real estate in your area, have a larger stock pile of cash, and several other units, I would recommend doing 15 years notes.