JackS, where are you from?
Have you done some touring, and if no or yes, what sort of touring are you imagining--panniers or just frame bags?
What sort of riding have you done? On what sort of bikes?
Actually riding a bike will always be better for getting an impression of how it rides, but dont forget, your riding experience plays a big part here, as well as tires on teh bike and tire pressures too--and of course, test rides dont have the weight of panniers and so thats a tricky thing to evaluate.
re "The Surly website lists the Troll as the do-anything but of the comparison posts I read riders have raged more about the LHT doing whatever they throw at it and much more fun to ride loaded."
I had always read the opposite, and was supported by my experience with a Troll--and it makes sense, the Troll is a kind of mountain bike, and mtb need to be nimble for riding on trails, whereas the LHT is specifically made to be "trucklike" and slower steering.
For me, faster steering is more "fun" , and I set up my Troll with dropbars and have toured on fairly heavily loaded and it handled great (lots of factors come into play though, one has to be realistic about that)
But I'm a light guy, and so this probably helps with me putting 50lbs on the bike, as me+load= 185lbs=a lot of average guys.
As others have brought up, duty fees etc as well as airplane bike fees have to be taken into account, so without knowing whre you are from, you could very well end up with extra fees that are not small....and you still come back to the fact that you are buying a bike with perhaps little or no test riding, and some bikes may not be in stores.