Repairs and Maintenance are not cheap and shipping carpet/furniture/etc to Hawaii calls for huge price premium so I would be sure keep a reserve for replacements.  

Unit 3: $800 + utilities Total: $2,825Expenses:PITI: $980General Maintenance: $50/monthMaintenance Reserve: $143/month Other Fees (admin stuff like LLC, registration fees, etc): $70/monthTotal:  $1,243.Monthly Cash Flow: $1,582Cap Rate: 13.5%Cash on Cash Return: 45%I appreciate any feedback or advice on this deal as I am just starting. 

Do you have the reserves to pay rent and utilities for a few months of it doesn’t get rented out right away?

They don't build a proper reserve, failing to account for turnover costs, vacancies, capex, etc.

Any property you get into, though, you should plan to have a good capital reserve account to address the problems that will inevitably come up.If you're looking for properties that have stronger cashflow, I would look toward the South East of the USA. 

That product is more expensive and does require reserves after closing.

A solid exit plan reduces the risk of default.Check Their Liquidity: Even experienced borrowers can run into trouble if they don’t have reserves to cover unexpected costs.

The main reason I'm asking this, is to understand how much cash I need to save up in reserves before pulling the trigger on a deal like this?

Use an operating account for income and expenses, a reserve account for maintenance and taxes, and a high-yield savings account (HYSA) like Capital One's 4% APY for idle funds awaiting reinvestment.

If you're in the real estate investment business and must watch every penny, irrespective of your time, then by all means, do what you think will keep your expenses to a minimum.If, on the other hand, you are really in the business of creating profit by way of being a good marketer and a committed dealmaker, your creative energies ought to be reserved for doing what you do best (or intend to do best)...