I am going to honest with you. Working these types of shows is hard work! Yes it is fun, but between the set up, hours at the show and the tear down, the day(s) is really long! And that does not include any traveling that may take place.
Your feet and back are going to hate you. Make sure to bring extra shoes so you can change during the day. Bring a comfortable chair and take breaks often. If you can bring a friend to help you, Do it!
I just worked a show in town this weekend and it was almost 12 hrs from setup to tear down. My feet were crying and I had to take an extra day to recouperate. LOL But is was fun seeing old friends and making new ones.
Have fun at your show!