I've gone with nothing but the airfare booked. Off season you can get some good rates if they know you'll just head down the road. A couple of caveats I wish I'd known the first time. First, they may ask you at immigration where you are staying. Give them a hotel name, any hotel name. If you say "I don't know yet" they may force you to make a long distance call to book a room. Just have a name ready. Second, if you don't have transportation prearranged your driver will almost certainly try to steer you to accomodations with whom they have arrangements. Not necessarily bad, I've had it work out, but it helps to be clear that you want to rate shop. Let them know what your budget and your lodging plan is and they'll generally be pretty helpful as they'd like to be your transportation hook up for your trip.
