I would suggest renting something with some ground clearance, right away from the airport when you arrive. Almost everything you do in this area and in WY will require a drive. You will be able to do so much more, for much cheaper if you have a car. If you have a car with good ground clearance you will be able get to and go to even more places. Also shuttles to the Mountain from the airport are expensive.
We rented at the airport through hotwire and got a really good rate. The airport is really small so it's easy to get in and out of .
Airport is best bet.
We rented a car for flexibility and could explore on our own
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