I have been there recently, the people above have some good input, particularly the VIP lounge idea, I think its great, Aeromexico also has one (it could be the same one) if you join thier member club. It may be worth it to join if you want to have a nicle place to pass the time during a layover. Here is a link to some general info: http://www.aeropuertosmexico.com/Ingles/airports/dfe.htm
also I would not suggest going anywhere during that time chances are you will be stuck in traffic while trying to get somewhere and miss your flight.
My son is also going to Cancun with my brother and his family next week maybe you will run into them. have a good time its really beautiful and friendly.
