Coming from the US recently, I've dealt with US customs in the past. Pretty easy to import a car as long as it's 25 years or older. At the time (and still should be the same), no import fees (usually by the percentage of the value paid), but still may have to pay the paperwork fees ($30-65, been awhile so can't remember).
I've only dealt with freight boxes from the airport where the freight company gives me the paper then I go to US customs, and also dealt with shipping a car from the sea (boat), similar steps as above, get paperwork cleared then bring paperwork back before merchandise is released to me.
Not sure where the driver would have to go to. My guess, make sure the driver has the title and all papework (bill of sale, buyer's info, etc). US Customs has been pretty easy to deal with from past expereince with questions, but of course I've dealt with US Customs on the East Coast that's not directly on the border. They're pretty strict on paperwork and picture IDs. If the buyer or seller is not present (IE ytou hire a driver), they may require a Power of Attorney saying you give whoever the powers to take care of all this paperwork needed, etc. They may want the buyer's Power of Attorney, not the seller??? Since it's the buyer that is importing the car and lives in the States, FYI.
If you're planning on transporting the car yourself, I'd call them up or visit an office beforehand and ask them what's the physical steps needed; could you take care of the paperwork beforehand (day or two before the actual trip), where to take it, etc... Now if you deal with a company, most likely all the customs hassle will be including in their fees already. Just ask them what paperwork is needed (title, etc).
