I have driven across (almost) east coast to west coast and back. I have logged the mileage from Raleigh (NC) to Los Angeles (CA) via I-40. I guess it's about 2600 miles, beyond Barstow where I-40 ends, compensating for the segment I didn't drive east of Raleigh. Then again, I returned via I-10, all the way from where I-10 started and terminated my journey at the junction of I-75 and I-10. Sorry, didn't go any further east but took a north bound I-75 towards Atlanta. I guess it's another 2500 miles. I drove my own car. But if you are talking about public transportation, you may take Gray Hound.