Aaron Paul refrained from drinking any liquid, including water, for an entire day to authenticate his portrayal as dehydrating.
4 Days Out (2009) was originally planned as being a bottle episode to save money, but it ended up being the most expensive episode since the pilot, Pilot (2008).
When Jane gets out of bed at Jesse's place and goes to the kitchen to get something to eat, the cereal she pours is Cap'n Crunch Crunchberries. The same cereal appears later when Walter is going through the food that Jesse brought in the RV for their marathon cook session. This is presumably a veiled reference to Jesse's street name at the beginning of the show, "Cap'n Cook."
At around 33:30 there is what appears to be a dead coyote in the grass of the foreground of the scenic shot of the RV.