Insulating the Belly of my TT

Do you have a Jayco with the coroplast now? I owned a 19RD Jayco TT with the coroplast. Of all the complaints I had with Jayco I think the coroplast was somthing they did almost right. My Jayco had large voids or openings into the coroplast. Basically poor job of installation. I closed and sealed all those openings. I used foam and sheet metal in large openings, foaming the underside of sheetmetal before installing. My black water valve was enclosed. My grey water valve was not enclosed. The grey water valve was the only problem in cold weather. All that said, if I was going to enclose an underbelly I would want both valves enclosed. Seems like that wouldn't take much modification. Put heat pads on the tank. Run some furnace heat in the area. Use the coroplast and make sure all was sealed. The coroplast works. It was Jayco's sloppy assembly line installation. I never had problems down to about 5 degrees except for exposed grey water valve. We would dump water in toilet instead of in grey water tank. I sold the Jayco for other reasons. Jayco had some good ideas using the coroplast. JMHO.