Does your fare basis require roundtrip travel? Many F fare do not. If not, you could ask if they could split it into two one-ways, and then choose the option to overnight in ORD.
When you get to ORD, if elite, ask to standby onto the (illegal) MSN flight. Not sure the rules on this - it's not same day on the standby segment, but is same day from the connection? If that gets denied, then take the bus, knowing the separate one-ways means the discarded segment won't affect the return trip.