My teenager is making his first solo cross country trip and will be on Southwest (which he's not used to) and changing planes at Midway, where neither of us have ever been, so we'd appreciate a little help from the experts here. He's not a newbie flyer, having flown regularly since he was an infant, so he knows the basic routine.

Biggest concern: do you have to go through security to change from the B concourse, where he arrives, to the A concourse, where his next flight leaves from?

On the plane: does NW have seatback entertainment? The website just had info about wifi.

He's bringing a bag lunch, will he need cash on the plane for anything?

He knows about the boarding by group, but I don't know if the group he is assigned for the first leg will be the same for second - will it?

Any pointers appreciated.