Anyone have some tips on how to find a place to camp?

I'm going to be driving from VA to WI next week, and would like to pitch a tent somewhere pretty to make the drive less crummy. I'll pass near a couple large campgrounds, but I believe they are closed this time of year.

I can always just curl up in a sleeping bag in my back seat at a rest stop, but that wont be fun at all.

Any tips are appreciated!