Since all the casinos are within a short distance of each other - walking is probably the easiest and best way to get around. It's really very safe, too.  Unless, of course, it's 110 degrees outside and you feel like you might melt just by being outside. Then you can hop in a taxi and stay comfortable in the air-conditioning (except when you have to run from car to casino). There are even water taxis that will take you between the docks at the casinos. Hey, if you're going to take a taxi, you might as well go in style.

Renting a car is a good idea if you want to get outside of just the casinos area and explore the surroundings. This way you can take a day trip to places like Oatman. Grab a rental car at the airport.