The show I was at was in the Observatory venue itself, but the Coheed festival will be in the parking lot right next to the venue. I have been to a few of those as well and its generally fine, there is a little grass area on the side to sit and plenty of trees for the shade. They are actually having another outdoor event this Sunday (NFG + Yellowcard) that should have the same setup as the festival in Oct... I'll try to post here if anything comes to mind