Wow, Kasich could actually come in second. Would love it.
Second for Kasich in IL would not do very much, most likely.
It's direct election of delegates for the CD delegates (3 per the 18) with the remainder WTA for the state.
Cruz would likely fare better under this scheme, even if he finishes a close third, with the more conservative districts in rural IL.
The only place Kasich may beat Trump is in Crook County and the near burbs, assuming he basically takes the former GOPe Rubio vote. Keep in mind, however, that Trump did well in Detroit -- a basis of comparison for a midwest urban center.