I just put on snows on steelies as well and then drove to Ohio. Mileage sucks...low 40s at best. My best highway was over 50 to Oklahoma. The factors that are different for this trip: Snow tires (not low rolling resistance), heavy(er) steel wheels, more luggage (longer trip). But, overall, 40 is still okay.

2008 CRV EX 4WD
2006 HCH
2004 S2000

Past Hondas
2005 Pilot EX
2005 Accord EX V6
2003 Element EX 2WD
2002 Civic SI
1999 CRV EX 4WD
1998 Civic EX Coupe
1995 Civic SI
1995 Civic EX Coupe