I think that either Shia and Karen were just on set, OR, if they did film there, that they are returning something to the warehouse....or maybe the film does climax in area 51...
However, I think this cemetary info does fit with the theories some of us have had that Shia doesn't realize just how adventurous Indy is until he helps him out of a jam and they team up to enter the conquistador's tomb. I still think Hurt maybe one of the Cemetary warriors...we also now know where Mutt gets his sword from to fight with Spalko...
Unrelated - not sure if anyone has mentioned this...in the trailer we have the chase shots of the jungle cutter exploding and the blade spinning towards the truck...we also have the shot of Indy, Marion and Mutt ducking before impact: it would be absolutely classic Indy if Indy uses the rocket launcher against the jungle cutter, destroying it with that cocky grin of his, only to see the exploded blade heading right for them...grin wiped off his face...thoughts?