Are you talking about covers for the bed ends? If so, go to
PopUp Explorer - The ultimate pop up camper web site. They are called "pop up gizmos" or PUGs for short & they're sold on that site. They are made to order size-wise and people swear by them.
OR.... you can go the cheaper route. At Cabela's (which is the only place I've found that carries the GOOD blankets), buy some 'solar blankets'. They are either red or green on one side & silver on the other. One blanket will cover a full-size bunk end. If you have bigger bunk ends, buy several blankets ($13 each) and cut & sew a cover to fit. Attach with bungee cords on the corners & you're good to go.
Some people use 'reflextic' in their windows which is like the car windshield panels you can buy. I believe you can get this at Home Depot, Lowe's, etc. They cut 'panels' to fit into their windows for extra sun shades.