Roller Furling on a trailered boat?
It will probably be easier to stow the furled sail with the mast. You need to detach the forestay to lower the mast anyway. Detaching the sail and R/F rig from the mast would be more hassle than having to fold the sail in the first place. To protect the jib on the road, however, you''ll likely need some sort of cover for it, which you could hoist over the furled jib with another halyard while the mast was still up.