>>1266159what you want is a surly lad. They're not cheap, but that's the clear company that's about 'rugged durability' and perfectly fits your bill for loading it and riding trails with almost all of their bikes. Good for different reasons, but, Surly. If that's too expensive, a kona unit or unit x with gears are both pretty fucking bombproof.
You definitely want a new prebuilt bike, because you clearly don't know anything about working on bikes, so a used bike will be the opposite of 'rugged durability' with '0 issues', and not a cheap new one either.