We use collapsible sun shades I found on Amazon for $20 per pair. You need three (two pair gives you a spare) to cover the whole windshield. They tuck up under the roller shade and sit down below the dash with no other attachment needed. They are on the inside so it isn’t as effective as an exterior reflector but it does help. Look up Two Piece Spring Front RV Windshield Sunshade - Silver on Amazon.