I have the LHT with 26 inch wheels, but not the disc. I bought the 26 inch rims over the 700s, for personal preference. I also have no desire for disc, so if you could save money on the LHT and not get the disc model, that may be an option. I have had mine for 7 years and still feel no need for disc brakes, though they are fine too. I have toured, commuted in the Ozarks, as well as the Western Pennsylvania area, so it has seen a lot of hills, fully loaded, and the brakes are fine.
Both bikes are great. I sort of prefer the more horizontal top tube of the LHT. Keep in mind though, the 56cm LHT has a longer effective top tube length than the 57cm Trek 520. The LHT effective top tube is 57cm and the 520 is 55.7.

Both are good, it comes down to what you want.