If you already have a boarding pass from the point of origin, which you should, then you wouldn't have to check-in again. The only issue I would say is passing customs. The line can get very long at certain times of the day, and the wait can be easily 30+ minutes.

Assuming you made it out in a timely matter, the only transportation I would suggest is the Train to Central (assuming your friend lives close to Central) and enjoy a good dinner there.