I would check in with @Joseph Chiofalo they lend nationwide and focused on investors and they also have STR specific purchase programs that might be able to reduce the actual HELOC amount required.

So many people purchased in the hopes they could get in on the cash cow, but failed to see how temporary those profits would be.

Any suggestions on types of loans with the least amount of headaches? 

For example a buyer of a $500k home with an assumable (existing) mortgage balance of $225k would need cash to close of $275k plus closings costs.

That drive is quite a drag, especially when I travel 15-20 hours to Europe and land at midnight and have to drive another 2 hours back home in Sedona.I'm thinking of buying a small condo in a decent area not too far from the airport, that I can also STR while I don't need to use it (which would be 95% of the time) and offset the mortgage with... maybe even cash-flow a bit?

Online I found that tenants are not required to pay the difference between their vocher amount and any remainder of rent.

Requiring renter's insurance (separate from your property insurance) is also very important since they typically would not have the cash reserves to pay for a major damage such as water damage, ruined floors, fire/smoke damage, and you will be sued by 3rd parties if something happens to them while at the house if they have to go to the ER. 

You would need a vast amount of capital since the area is highly affluent, with some of the best school systems in Georgia. 

However, an additional amount should be set aside for CapEx and repairs.While the 50% rule provides a useful starting point, it’s essential to recognize that it primarily covers operating expenses and not CapEx or repairs.

Great paying tenants in place and it cash flows even with my almost 10% DSCR loan.