When I was a kid and first became fascinated by the Interstate Highway System, I quickly learned to read maps. Then I discovered Canada, and was absolutely awestruck. Canada is *big* ... like, really big. And almost all of its land-mass is *empty* ... like, really empty. I always thought it would be funny to drive from the town called Caribou in Maine to the town called Caribou in Alaska. It certainly meets the definition of "from one end of the USA to the other" although ironically, if one did drive from Caribou to Caribou then you would spend 4115 of the 4444 miles between the two towns not in the USA but in Canada. Anyone want to split the cost of gas with me for this mother-of-all-roadtrips?

PS> If you required me to stick to the Lower-48, my answer would be "Kill Devil Hills NC west to Ocean Beach, San Francisco CA." Almost exactly 3000 miles if you use I-40 across from Raleigh to California. I should know; I've driven it FOUR TIMES.