At this time of the year temperatures are generally not a concern, so long you do not drive with the AC cranked up like some people do.
Now as far as the hotel if you do not keep your temps below 75 and keep the animal in the bathroom temps will not be an issue either.
Now while you are excited about your 40 gallons tank, keep in mind that this is designed for adults and an hatchling or juvenile which is mainly what you find at show a 10 gallons or 6 to 12 quarts tub will be better suited for an enjoyable problem free experience.
There are some great vendors that will be in Charlotte, and it's a good show.
Among those vendors
Limey @ Royal Reptilia
Grant & Mary @ Wreck Room Snakes
Frankie @ Fat Boy's Ball Pythons
Dwayne @ Twilight Ball Pythons
I also recommend to use the list already on the website and check their reputations on the BOI http://www.faunaclassifieds.com/foru...splay.php?f=13