In The Things We Bury (2014), Cal told Whitehall that he wanted to reunite with his family in the "Afterlife". This episode revealed that he was talking about the Inhuman's sanctuary in China and not the life after death, literally.
When Fitz is packing his stuff, he takes down a selfie of himself and Simmons taken at the Incan Archaeological site in Llactapata, Peru in season one's 0-8-4 (2013).
The battering ram sequence showing the door integrity at the cabin plays out much like a sequence in Captain America: The Winter Soldier (2014) when Nick Fury is cornered by Hydra Agents. The battering ram was used on his vehicle.
Fury's toolbox has an outer layer of vibranium, the same material Captain America's shield is made of.
Coulson mentions he had Deathlok keep tabs on Doctor List in the last 6 months. This places that assignment in between episodes 3 and 4 of this season.