It is my understanding the Priceline OWs are location specific. Some do, some don't.
They are only for one-ways within the same market, such as JFK to LGA, or MIA to FLL, etc.
Before your trip you may want to walk around your airport rental parking lots and check if they have cars with out of state plates - the closer to your destination, the better. Often station managers are willing to negotiate a decent price to send those cars in the right direction. Obviously your size requirement makes it more cghallenging but it can't hurt to check.
This is usually no longer the case, since most locations are corporate-owned with a shared nationwide fleet. So cars don't need to go "home." Rates reflect mileage depreciation and difference in demand. Hence the FL one-way specials, as demand changes with the seasons.