Hi Larry
I'm curious as to why you dont believe in your LHT?
If the Trek gave out on you, you'd still be out of pocket due to the expense of getting it up to scratch.
I wonder what that money might do for the LHT.
If you replaced the cassette, bottom bracket, free hub, chain and front rings, serviced the wheels (spoke tension and bearing grease), in what way might the LHT prove to be unreliable?
I understand spares for 700c might be thin on the ground in some of those places but you'll be touring and not mountain bike racing.
Oh and repack the pedal grease and tension bearings as well as repack the headset bearings.
Has the Trek more spokes than the Trucker?
The trucker is purpose built and I'd lean toward trusting that build if you've done the above which is what I'd do for any upcoming tour of greater than a months duration.
Are you familiar with Cass Gilberts blog
http://www.whileoutriding.com/
Lots of South American stuff in there and Cass favors 29 types of bike although he's also done 26er.
Good luck with your choice and look forward to hearing more about it.