I would have to double check, but I think the lawn trailer is 10 cubic feet. I would bring the mower and lawn trailer on a utility trailer with a 6.5'x12' deck on it that we could potentially use to move rock. I would just need to fabricate some sides to contain the rock. I can try to get the sides made this weekend, but I can't guarantee anything. Depending on how much rock we are moving, I might also want to hook the trailer up to someone else's vehicle that has more towing capacity. The rock might be a little too heavy for my Equinox; towing the mower is already pushing it.