For Kathy (Bugsbunny..) we booked KOA over their website 2 months ago, as campground itself doesn't open and managers don't arrive to check messages until May.. There are others closer among 10 or so campgrounds listed by Oshkosh Visitor's Bureau, though many do not offer enough electricity to run the magic cool box on the roof... Listings are at
http://www.oshkoshcvb.org/eaa.cfm after all the hotel and motel listings within 50 miles...
For $40 you can join EAA and camp on airport in "Camp Scholler" which is 1 mile square grass field, with showers and stores at edges, but no hookups, and daily rate around $15... No reservations, it's first come first served, and very "communal". I'm betting there will be boondocking Airstreams there, and there is a section partitioned for generator use, that may permit them past midnight...
Having flown in 14 years ago, and read stories of last few years, arrivals and departures are not for the inexperienced, the incompetent or insecure... Even if 1 pilot in 1,000 is grossly unqualified that means a near disaster every few hours, as 10,000 small aircraft try to squeeze in starting over the same water tower in Ripon over a 2 day period... The FAA sit on top of the tower with binoculars and radios and a sense of humor, enjoying the show mostly, until some buffoon can't maintain speed or altitude or heading and traffic patterns get scrambled..
JB McG