I concur. Rent a "not so new but reliable" vehicle for the duration of your travels even if you don't plan to drive it.
I have been renting cars for the last 3 years out of POP airport (Avis/Budget). Two weeks/unlimited mileage runs around $600 US before insurances for an SUV. The vehicles usually sit parked for the majority of my visit but it's nice to have one available. Check with the resort and make sure they have parking. It will be cheaper.
Insurance is the killer. If you can avoid it by using c/c coverage plans do so. Last year I booked using easycars, paid $300 for a 4-door car, 2wks/unlimited. The easycars web site offered free liability insurance with the booking. They put an $800 freeze on my c/c in lieu of waiving additional insurance at the airport, that was cancelled when I returned the car. I was skeptical at first when I booked because you pay easycars not Budget but it worked like a charm. I presented the pre-paid booking reciept and I had no problems at all. Whole thing cost me less than $400. I recommend checking it out.