Ha ha, oh wow, that's some classic shit suburban force-everyone-onto-arterials planning there. You can only cross Hwy 41 on Deerfield, Park, or Clavey. A little to the east of of 41 is a tiny little drainage ditch only crossable on Deerfield, Clavey, and a footbridge behind Deerfield Highschool.
So from Highland Park, Park->Ridge->Painters Lake->Footpath to Deerfield HS->Waukegan->Pedestrian Crossing over metra tracks just south of Chapel Ct->Chestnut to Metra.
Pace Shuttlebug from Braeside metra on the UP North Line to the Northbrook stop on Lake Cook Rd.
By bike...no dice. I've only got the Lake County bike map and they're not giving any clues.
Julie, Can you just take the Milwaukee District North line from the city all the way to Deerfield? It would require going east-west thru Chicago, which from my experience is almost always preferrable over suburban riding. From your neighborhood their are two stations that would be an option: Mayfair Station @ 4357 N. Cicero or Forest Glen Station @ 5301 N. LeClaire