I looked at the kits. It looked like they have the pre-cut insulation backed by vinyl, but at twice the price of 4'x8' insulation. $50 is $50, so I chose the less expensive way. It doesn't look great, but I don't think the kit would look great either. I plan to cover the whole thing with ... something? Oh, and I only had to buy 3 sheets ($36) because I also found some sheets along the road on the way (blew off a truck recently?).
Thanks for EVERYONE's information!!! Read this string, shopped, bought, and installed ... all in one afternoon.