I would also suggest NYC, but if you go into EWR the airport monrail takes you directly to the NJ train station. From there it the train takes you into Port Authority which is close to Macys and Times Square. Once in town get an all day metro card at $4.00 it allows you to hop on and off the subways and busses all over town.
What day trips you take depends on where you start. I have gone to Key West for the day. Walked the entire island so did not have to pay for a cab or rental car. New Orleans is also good with the the waterfront and French Quarter. I have not gone to MSP to shop at Mall of America for the day, but know many who have enjoyed this day trip. I have even known of co-workers who have flown to MYR, ATL, TPA ....etc just to get in 18 holes of golf. Day trips boil down to:
1) Can you get on standby there and back
2) Once there is it easy to get transportation to what you wish to see and do
What day trips you take depends on where you start. I have gone to Key West for the day. Walked the entire island so did not have to pay for a cab or rental car. New Orleans is also good with the the waterfront and French Quarter. I have not gone to MSP to shop at Mall of America for the day, but know many who have enjoyed this day trip. I have even known of co-workers who have flown to MYR, ATL, TPA ....etc just to get in 18 holes of golf. Day trips boil down to:
1) Can you get on standby there and back
2) Once there is it easy to get transportation to what you wish to see and do