Short term rental creative finance

Hey BP - apologies in advance for the naive question here: how do I know how much is too much to offer for a creative finance deal on an STR in a vacation only market?

Seems like the beauty of creative structures like Subto/ Seller Finance/ hybrids is that you can pay more for a property and still get a better yield if the seller will agree to your terms (usually a low DP)... but offering more than market obviously increases risk if you are forced to exit. In a typical metro market, I've heard many say "buy an STR that still cashflows as a LTR so you have a backup plan" ... but in many vacation-only markets (think Smokies, Destin, etc.) no property will cashflow as a LTR anyway. So ... how do I know how much is too much to offer in these markets? Is it simply a matter of calculating the DSCR of the property and ensuring it meets some reasonable threshold? Is there a specific cap rate you target? Or will you simply not offer an amount above what recent comps indicate is fair? Would love to hear your thoughts