I think you are better off buying a unit and selling it when you are finished with your trip. In our experience
you will just scratch the surface of what you want to see as you cannot drive and experience the country at the same time. You will be staying in many places for several days at a time and those days add up quickly. We thought we could see the USA in ONE year and now we think it would take about five years. Whatever you do, get out there and enjoy the world one day at a time, there is so much to see and do ,and when you get in a RV you will be amazed at the freedom you have. Regards Bob