I don't know about U of I or IU's enrollment policy, but at some schools you only pay tuition if you are actually taking classes, so semesters/years of field work are not paid to the university (the catch being that field work costs money, but that is somewhat easier to find funding for). Other schools have continuous enrollment requirements where you pay tuition no matter if you are in residence or not, which would suck if you were unfunded.
I know this doesn't help with the first or second years at all, but it is something to think/ask about.