Over a birthday lunch, the question was pondered as to whether you could visit all fifty American States in three months. A cursory look brought up an article saying it could be done in 160 hours. So, the answer would seem to be yes, though a punishing schedule.
There is also a great article on XKCD (to be honest, everything there is fantastic). You can read the article here, but they conclude (via a reference to another blog) that in 24 hours you can visit about 19-20.
Why 2023? Well, that's probably how long it would take to save up for the trip.