My trick, which I have posted here before, is to reserve the size car (for me that is usually compact or intermediate, whichever is cheaper) you would otherwise get with one of the major rental car companies. A convertible may be twice the price of that car. So, what you want to do is PRICELINE a convertible, bidding up to amount you reserved your other car for. If you get the convertible (and you probably will), great. If not, you still have the other car at a reasonable price. The only flaw I have discovered with this system is that you will more often than not, end up with an Alamo car (not my favorite company on Kauai), but hey, it's a convertible!
There is NOTHING like a convertible on Kauai! You won't regret it!
