Even though Kununurra is small, interesting things tend to be far apart. The town doesn't have a local bus service but short hops around town can be easily done on foot. Trips further afield will require a car and getting to places on rough dirt roads need a 4WD.
Driving around town, you will encounter few cars and not a single traffic light. On street parking and carparks are free. Most corners, even major intersections, follow the give way rule and stop signs are given the same regard by most local motorists.
Outside town, the long, straight stretches of highway give you a chance to put the foot down and eat up some miles. If you are inexperienced in country driving, watch out for oncoming road trains that can push you off the road with their draft, and kangaroos at sunset.
The major car rental outfits have offices in town and the airport:
Avis Car Rental
Can arrange pick ups from the airport.