You're too late! GenCon has come and gone for this year, but I assume you're planning for 2005.
(i.e., next year!)
Okay, anal retentive mode off.
You do realize that it's only about an 8 hour drive from where you live right?
I would just drive if I were you.
8 hours is like 3 tanks of gas, tops. Leave Wednesday morning, you're there Wednesday evening, and you're good to go. That's 570 miles according to maps.yahoo. Most cars can easily get 25mpg on the hwy, and so you're looking at 22 gallons of gas. That's 1.25 tanks there, and another 1.25 back. At $2 per gallon, you're looking at $44. That's a heck of a lot cheaper than flying.
Hotels are pricey there. If you drive, you can stay further away, but it will seriously detract from your GenCon experience, so it's not really worth it. I did that in Milwaukee, and really hated it. But it was more of a requirement there.
Anyway, hotels will run you about $120-$150 a night. With a roommate, it helps a lot. The hotels are really nice, though, and there is plenty of space within walking distance. I think I paid $300 last year with a roommate. You might even try using PriceLine to name a price earlier. Maybe you can do that early enough that they won't realize you're booking it during the Con. I suspect they're smarter than that, though.
Eats are not too bad. There are fast food places within walking distance, though not a lot from what I recall. I know there was a Subway and a McDonalds nearby. To save money, consider taking your own snacks for breakfast, or to snack on during the day. Or, you could just go on the GenCon diet like I did a couple of years ago (not intentionally). I just didn't eat very much, and all that walking around with that heavy bag, I lost 5 lbs!
Then there are the inevitable books, and games and dice, and miniatures, etc, etc, etc. You know your budget better than I do. Budget wisely, and look for bargains. I suspect that if you wait until the last day, you can probably actually haggle with the dealers.
