Go west, young man . No seriously, rather than build a multi-leg trip through ORD-STL-LGA where you are risking weather problems (November/December weather has been known to interrupt travel at all of those airports a time or trillion times , consider flying to California or Washington. For example, on Dec 5, you can take direct flights ORD-SAN-ORD for $219.20 and get 3446 EQM (almost 6900 DEQM) -- even better, you leave ORD at 8:45 am and are back at ORD by 8:40 pm.

The other thing to consider is if you are ok with an overnight, you probably still want a different city than New York for your overnight because overnights in NYC hotels are generally more expensive than other nights in other cities. NYC well just isn't cheap and if you are planning on getting into Manhattan so you enjoy your overnight -- even more expensive.