Either way, you both are looking at 35-50 minute commutes.
Taking the EL is your best bet; there's a Metra, but that goes to the Loop so is of little to no use for NWH.
Also, the advice of others is true -- Evanston is a great little suburb right on the lake, but it's horribly inaccessible to freeways. The only good thing is since you take sidestreets to ORD, the journey time is almost always the same; I used to allow 35 minutes (in the car). If you lived in Chicago, the ride could be 15 minutes (no traffic) or 1 hour and 15 minutes.