I've never been, but I've heard it's usually hosted on national forest land. If that holds true, then I'd guess it'll probably be held at Chequamegon- Nicolet National Forest, which is the only national forest in Wisconsin.
Then again, maybe not. It's deep in the Northwoods, where logging and tourism are bigger industries than agriculture and industry, so trains are scarce and IMs nonexistent, and what few trains do come through will be junkers. The closest shipping/industry hubs you'll find are the ports of Superior/Duluth and Green Bay. It's 50 miles to the far Western edge of the forest from Superior, or 55 to the far Southern border from Green Bay.
Transportation would therefor be an issue. Maybe you could cover 50 miles on foot- I won't deny it's possible, though food would be hard to come by as there aren't many towns up there. With some effort it can be covered in a single day by bicycle (I speak from personal experience), though hilly terrain might add another day or two. But traffic is light that far north, and most summer traffic is rich FIBs and people from South/Central WI heading to their family cabins- which may be problematic for hitchhikers.
Commercial bus lines don't even exist that far north- Wausau is the end of the line, and that still puts you 100 miles short unless you go to Green Bay or Superior, but we've already discussed that.
Sorry to ramble, just covering all the bases. I'm just not sure how you'd reliably move large numbers of people to the Northwoods for a festival, so maybe they'll hold it further south (which would be easier to reach without a car) but I can't think of any good places for a festival there.
