I found that Crossroads does offer the Extreme Winter Pkg on the Grand Reserve Trailer. This has heating pads on the tanks that have a separate switch to turn them on. I noticed some RV dealers that had 2016 Super Lite Sunset Trails with the same package listed on the sales thread but no info on it. It was never presented to me by the dealer to be an "extreme winter pkg" but I think I'll give him a call to see if they had any more info on it. I did notice on the CR website that the Grand Reserve section does list the EWP, but the Sunset Lite does not have anything listed as a "cold weather pkg". The search continues.
2012 Toyota Tundra DC 4.6L V8 with Tow Pkg