buying a car

Me and a friend are planning a road trip from Boston to San Fransisco after we have left school (next summer) At that time we'll both be 19y and both have driver-lisences (dutch ones cause that's where we from)
Because we're planning to stay away for several months, hiring isn't a option because it will be way too expensive so we want to buy a car when we arrive in the US.
Our question is or that's possible without an adress in the US. unfortunately, we both don't have any relatives/friends in in the US so we can't insurance the car on an US-adress...

Thanks for your help!

Some of the best information we have ever seen for visitors from Europe considering an USA road trip can be found in Andrew Vincent's new book: "Drive USA". In the book, he provides some clues and tips about purchasing a car for use on road trip. For more information: http://www.roadtripamerica.com/links/international.htm

You can purchase a car and insure it to.There are some procedures involved.My friends from Germany did this for an extended stay and purchased rather that rented.They also arranged to sell the car back before they departed.I do not know the details but it can be done.