EM, That size 5th wheel ought to work for traveling just fine.
Mine is 30 foot tip-to-tip, and I would not want to live in anything smaller, or pull anything bigger.
I pull it with a HD 2500 long bed duramax/Allison chevy. The tow vehicle is more than capable, and under all the spec. maximums.
I am pointing this out to you because I think you might want to use these facts to begin your search for the right truck/trailer combo.
Now, ultra light trailers. I do not want a trailer more lightly constructed than the one I have now. If anything, they should be stronger than they are. More insulation, double pane windows, no air leaks.
The only advantage to an ultra-light trailer, is you might be able to pull it with a half ton truck. I don't see that as an advantage because the 3/4 ton truck is a much better hauling platform than the 1/2 ton.
So that is my opinion, based on my experience. Do what you wish with it...Jim