Weight to tow thru mountains

I'm looking at 2 trailers that should be well within my truck's towing capacity on paper, but it will be towed thru mountains (Smoky and Rocky) at least part of the time. The trailers are very similar, but one has a small dinette slideout, and is 1000 lbs heavier. That small slideout gives a little more kitchen space, which my wife would like, and more room for the dog. (Wife will accept either trailer.)

Just wondering whether I'd regret the extra weight driving in the mountains.

2013 Tundra Crewmax 5.7 w/tow package
dry trailer wts 5400 vs 4400; gross 7500 vs 6500; 23&24 ft boxes.
Jay Flight 23RB vs 24RBS w/extras

Thanks!