I think the 2108FBS is going to be significantly out of your weight range. You're going to be severely limited in your choices with a 5,000# towing capacity. Even at that, a safety margin of 10% - 20% is desirable, which reduces your choices even more. If I recall the details correctly, most tow capacities assume one driver of around 160#, a full gas tank and no additional people or "stuff" in the tow vehicle.
I'm not familiar with Winnebago's TT offerings but you may find that you'll need to explore a wider range of manufacturers' ultra light offerings. Fortunately, more and more choices are becoming available.
2002 Itasca Suncruiser 35U