I've been to PNC (The TRL Tour with Destiny's Child headlining) and the lawn seats are pretty far away, keep in mind I was using binoculars here and there when I actually had seats in like the 3rd section. Not sure if they changed the seating at all but yeah, I wouldn't touch the lawn seats. I wonder if the show there is canceled.
You can sorta visualize the seating and all here, using the 3d seating chart. I was in section 304 using the binoculars!
http://www.livenation.com/venue/pnc-bank-arts-center-tickets#
Actually, the main picture there looks like the lawn area.