Tips: DO get the parking lot across from the building. It's 30 bucks, but it's worth it because you get to stay as long as you want, from dawn until after the show at no extra cost. You can keep going back to your car, and see your car, and put your stuff back in it when it's showtime.
DO NOT park in the scuzzy parking lots down the road. DO NOT leave your car at the metro station and take the train. The fees will be enormous, and you will have no place to put your stuff, and you will have to ride it back at midnight. There is a huge metro station right down the sidewalk from the center, but if you leave, you do so at your own risk as you may lose your place. People will save it for you for a lunch or bathroom break, but if you are gone when they move you up (several times a day) you might get left out.
DO use the bathroom in the Discovery store next to the MCI center. It's clean and nice and they don't mind. DO NOT use the bathroom in the Burger King down the road, it's small, gross, and there's always a long line.
The Burger King's food is not bad, and the Ruby Tuesday's around the corner is good too.
The band will come in via garage door on the side of the building facing the road that leads to the Burger King. If you sit there you will see them, it's going to be your only chance, there is no behind the building or fence situation like at other venues. The door leads under the building, they go in and out from there.
When they tell you not to run going down the stairs, don't listen to them. Everyone esle runs anyway, and it will cost you a spot.
Sigh, the memories.
PS- Go to the bathroom before they open the doors, and don't drink anything at least an hour before. You don't want to have to go to the bathroom once you have secured your GA spot, especially if you are on the open floor or around the outside of the elipse, you may not get your spot back, and you waited for it all day!
If anyone tries to push you out of your spot, stand your ground. You earned your spot, don't be a pushover. It's your chance to see U2, keep it!