I'm a bit confused on where to go with all the choices.   Trying to optimize 3 variables -- 1) We're riding a mountain bike tandem, so I'm interested in great cushioning and softness, 2)  Toughness -- want something as reasonably puncture resistant as possible, 3) Anticipate some mud and difficult dirt environments so need good traction but not crazy to the point that its creating lots of rolling resistance.   

Finally, would like a "foldable" replacement so that I can carry a spare on the trip.   Leaning toward 2.4" width or larger.   

Any recommendations?   Much appreciation.   David