I'm a veritable expert, possibly a top level professional (currently retired) at dumb questions. I'm only average at answering dumb questions, though. Fortunately, I have a little experience in riding surfaces which you may find yourself riding.
I've toured on Schwalbe Marathon Dureme (which I think means durable) and found they are heavy, very resistant to flats, and last for an estimated 10k miles. They were not a particularly comfortable ride. I have used Marathon Plus and currently use Marathon tires on my current ride. I've experienced the same flat resistance and the same lack of comfort. So from the touring point of view, on pavement, at least, they're great. But I experienced a decidedly deficient lack of traction with tires of this type on gravel. In one case, I simply veered left into the other tire track and found my wheels slid out from under me, while coasting downhill, maybe 12 mph. I slid, drive side down, for 20-30 feet. (BTW, you should carry a spare derailleur hanger with you on tour.) I might have avoided crashing if I'd reduced the tire pressure to 40 psi or less, and had more compliant tires. The marathon tires are anything but compliant. However, compliant tires are generally less resistant to flats, so there's that. A semi knobby tire that has a center ridge and is cushy at 35-40 psi but can run pavement at 55-60 is what I'd look for. I like the Surly Knards if they will fit, at 41mm.