OK, we know that rolling resistance and a higher incidence of pinch flats are inversely proportional to tire pressure. In other words, the higher the pressure, the lower rolling resistance and the fewer pinch flats.
However, lower tire pressures mean a more comfortable ride and in the absence of suspension seat posts, suspension stems, or suspension shocks at the either end of the bike (a touring bike), having a lower tire pressure may be the only remaining means of smoothing out the ride. I am assuming that the rider wears cycling gloves and will stand in the pedals to distribute her weight more evenly when anticipating bumps.
Tire width is dictated by the load the bike must carry and the worst road conditions that will be commmonly encountered during a tour. So, given 35 mm tires with recommended tire inflation of, say, 50 to 85 psi, what is your experience / recommendation for rear and front tire inflation pressures that will work best for sustained rough surfaces such as those generally found in double track? Would there be any significant improvement if, assuming they would fit the frame, a wider 40 mm tire were used? 50 mm?