SERENITY Crew Members Briefly Reunite for... Something

Nathan Fillion tweeted a photo yesterday that set the nerd world ablaze. It showed Joss Whedon, Adam Baldwin, Alan Tudyk , and himself posed in what appears to be a forest. Could they be filming cameos in Whedon’s The Cabin in the Woods?  Could they be discussing a Firefly reunion? Eh, it’s likely just a camping excursion but that doesn’t kill the fun of dreaming.

Please comment with your guesses at to what is going on in the photo.