I was tempted to use a longboard but it just didn't sit well with me. So I managed to do it on my shortboard and am so happy I went with that decision, although my ankles would say otherwise
Check out http://pavedwave.org/ (The Soul of Distance Skateboarding). On the forums you'll find tons of advice (skateboard equipment, technique, nutrition) which can help you achieve awesome goals. You can also find events over there. If there's one time an event close to you you should really check it out, it's a great experience to come together and ride for 24 hours! (sound funny huh)