STR down payment options?

[Cory Lucas]

We've been wanting to do STR for awhile now, down payment is of course the big factor keeping us from doing so at the moment. So, I'm curious as we're going to see if we have enough equity to help, which you all would recommend? Cash out refi, 2nd Mortgage, or a HELOC? I love the idea of a HELOC, but I'm thinking that might not be as adventitious as a Cash out refi or 2nd because of the likely high dollar amount that would be getting paid off when doing an STR.

And/or for those that are in the game other creative ways to finance the down payment? Things like seller financing or is there some other creative way to structure a deal to do so, like utilizing future rents somehow? 

Thanks in advance for the time and feedback