It's never too early to see what rooms are available - especially as the hotel lottery is less than three months away as I post this.
Here's a spot I stumbled across a few years ago: Emerson, just south of I-465. A few "amenities" (Rally's, White Castle, Steak & Shake, McDonald's, Firehouse, and a few others, plus a WalMart), plus four hotels, all of which have rooms available for GenCon weekend (I checked for 7/30 through 8/5):
Super 8 - $85 for two doubles or one queen
Holiday Inn Express - $155 for two kings, nonsmoking
Red Roof - $153 for two fulls or one king
La Quinta - $209 for two queens or one king