There are always scalpers/buyers on craigslist. If you're looking to trade, make a post and it'll grab someones attention. If a scalper thinks he can make a buck off your tickets, he'll work something out with you.
But you won't find anyone willing to give up Illinois for Illinoios State.
Illinois State for North Texas is a fair trade. Honestly, I'd just sell your 2 tickets then use that money you sell them for to purchase tickets to the North Texas game.
It's actually in your favor. I know you said not to use stubhub, but you can clear around $35 a ticket for the home opener. Then North Texas, you can buy right now for $30 each on stubhub. Or, scalp for 15-20 bucks on gameday...