Cornhole boards are light, but the painted or vinyl-wrapped playing surface chips easily against a hard edge, so the main job is protecting that face, not managing weight. Face the boards together, pad between them, and they travel like a single flat panel.
Pro tip: If the boards have custom artwork or a team logo, take a quick photo before the move in case a corner does chip and you need a reference for a touch-up repair.
Watch out: Painted or vinyl-wrapped cornhole surfaces chip easily at corners and edges; always pad between two boards rather than letting them touch directly.