When I first started coming to the DR, the Montero was all I rented. Granted I didn't leave the city, but I remember gas mileage was crappy but it off roaded like nobody's business.
Now I normally rent CRV's and RAV4's since I drive quite a bit. Well on my last rental I had a breakdown and my car rental guy offered me a Montero that runs on propane and gasoline. With $2,000 pesos of propane I went from Santiago to Sosua and down to Santo Domingo before that gas gave out, then all I did was flip a switch and was running on gasoline.
I highly suggest doing that retrofit to a Montero, it really takes the bite out of the fuel cost on that gas guzzler. I have already put in my request for that Montero again LOL