I have some information on what appears to be your particular line (my data base #0026). However, the dates don't quite match up. There are lots and lots of Casner/Carsner people in IL. Because there are researchers out there on that particular line, I have collected only enough to insure that my line is not connected to it (yet). As I come across further information, I will continue to add to the db.
A couple of suggestions if you haven't already done this.
(1)Since you know the counties in which your family settled, I would recommend you correspond with the historical/genelogical societies in those counties to see what information they may have on your line. Often these will supply wonderful information.
(2) Locate either a volunteer person or a paid researcher in those locations in IL and see what they can find for you in county birth/death/marriage records, land, cemetery records, local histories, etc at the libraries.
(3) Locate either a volunteer person or a paid researcher who could do the same at the IL state historical/genealogical library and newspaper archives. I have located wonderful information out of the newspaper archives from many states.
Sorry I could not be of more assistance. Good luck in your search.