Yes, you can. Freeze long slices or squares in an airtight container with layers of either cling film or parchment paper between the slices/squares to prevent them from sticking. Freeze for up to 1 month. Freeze the entire block of the rocky road that's already set after being in the refrigerator by removing it from the pan and wrapping it tightly in a double layer of cling film, leaving it on the parchment paper. Place in an airtight container in the freezer and freeze for up to 1 month.  Defrost slices/squares or entire block by placing the container with the rocky road still inside in the fridge overnight to thaw. Then place on the kitchen counter for a few hours until softened enough to slice and eat.