This is totally possible. Maybe not for 1600 miles but 1000 for sure. I do this for 500-800 miles regularly. Sometimes 1000+. Speed limit is 70mph on most US highways and the unspoken agreement is you can go 8 or 9 over and not get pulled over. In metropolitan areas you can typically go even faster on the beltway, almost everyone does. You train yourself not to need to piss as often, so you piss while you gas up. You don’t eat until your drive is done.

Do the math with 90 mph, although to be fair, I only average 80 to 85 probably. I only do 1600 with multiple drivers. I live in Ohio but I take people to the mountains out west all of the time. Sometimes I drive to Colorado by myself though without stopping other than gas. Also, I’ve done a thousand miles on a motorcycle in one day. Now that is a feat.