Camp Easy has the best vans of Iceland, no doubt about it. I specially recommend the 4x4 vans so that you can go into the highlands. This gives you access to so much extra spots to explore.
Note that the CampEasy pick-up and drop-off office is 5.5 km from the airport. They offer free shuttle service to/from the airport and nearby hotels only during their office hours (8 am - 4 pm). If you are picking up or dropping off outside of the office hours, you will need to arrange alternative transportation to/from the airport.