I'm not sure CanoeU92's neck/shoulder soreness is a fit issue, perhaps just slight lack of training as others suggest. Surly LHT/DT AFAIK can be fitted with brifters w/o much difficulty. LHT/DT have relaxed angles/long wheelbase which softens up the ride a lot though my 80's steel/non-susp Rockhopper MTB fork soaks up bumps much better. For trails the LHT can be fitted with wide tires. One might not need 50mm/2" tires but at least there's the option there vs many other touring bikes.

Once did 40 mile ride on sport-touring bike (32 mm tires) with last 10 miles on the C&O & the ride was punishing--& that was when I was young & fit. Folks have varying tolerance for bumps so YMMV. On my DT I'm going to try Schwalbe Marathon Supreme 50mm tires as rec'd by a poster on another thread--more for occasionally bumpy local road/conditions but perhaps also for eventual GAP ride.