Vans Warped Tour 2011 @ Comcast Center?

How does the Vans Warped Tour work if the comcast center is partially closed in....are there actual seats or does everyone have to stand & why are there different prices for tickets on the some of the sites (some are $45, some are $60, $141, all the way up to $500?) ??? Also, I want to meet The Ready Set singer, so what happens when you go to the meet and greets exactly? Can you take pictures with them? Are the meet and greets at a certain time, or are they all right at the beginning of the whole concert? When The Ready Set goes on to perform, how can i make sure i'm right up front? Any help is greatly appreciated, thanks!