This July, TREKOFTHEAMERICAS, is doing the first ever truck camper caravan from Texas to Argentina. Beginning in McAllen, Texas the folks from adventuretrek.com has organized this trek of 120+ days, 9 countries, and two continents.
You can join, but first look at the website. Good highways and pleasant daily drives with a veteran trek leader who has done this trek over 13 times. But don't expect KOAs, just a great adventure that's so hard to believe you are there.