Lets create a list for maintenance (do these monthly/yearly) :1) change Furnace/AC filter2) change fridge filter3) get a guy to move the lawn/get rid of snow4) replenish water softener salt (if there is one)5) clean gutters (yearly)6) power wash (yearly in Florida/Carolina and other wet climates)7) pest control yearly?

You just have more options.By using the BRRRR strategy with a HELOC you replenish the HELOC when you refi the rental property.

Patience until my funds replenish? 

Keeping 20K - 30K in reserve that you can replenish with surplus employment income should get you through the vacancies and capitol expenses that come up like a new roof and renovations.Once you retire and all properties are paid off, assuming you have not gone bankrupt along the way, you can liquidate and live the good life.

. $50k) for your entire portfolio then just replenish if used?

I do BRRRR, but I use my own cash to purchase and rehab and then refinance to replenish my cash funds to do it again.

I'm guessing that would open things up to where I could borrow against house 2 or 3, pay off my HELOC, then use my HELOC for purchasing deals (then refi out and replenish HELOC)....

Do you buy in bulk and store in a centralized location, and pull/replenish as needed?  

Buy it, manage it well, and let the cash flow replenish your cash stash.

That doesn't even include cleaning supplies or replenishing the consumables