If you're even remotely thinking about going to the AirVenture Oshkosh air show, you're probably to late to get a decent place to stay within a reasonable distance. We've attended numerous times and find that it's not for nothing that it's called the largest air show in the world...
I'd recommend you check out Appleton, Wisconsin for a base of operation while attending Oshkosh... it's about an hour away on really good highways and a beautiful town with lots of amenities...
Welcome to the U.S., by the way!