I won't speak to a specific TT as there are so many and I wouldn't know their weights.
But as to cold weather, I sometimes think the cold weather packages are a water for anyone not using it in sustained sub zero temps.
For example, my trailer is old and poorly insulated. I still have no issues during the winter where I'm camping in temps that are at or below freezing for 7 days. The only difference is how often I need to charge the battery due to the furnace fan being on more often. But it's always comfy. And during that 7 days, I'm only in it from about 7pm to 5am. The rest of the time it sits with the furnace turned off. Never had any freezing issues. This may vary from trailer to trailer, but mine is a 1987 model with paper thin windows and no under carriage insulation