I’m not particularly tall ~5’6", and can walk all day with an average pace of 6.5km, with a light load (rucksack, or day bag). This is in a hilly area, using generally unmade footpaths (albeit with defined alignments). I choose significantly hilly routes whenever possible too.
I consider 50km in a day to be well within my comfort zone, and could do further if pressed. Generally taller people would find it easier to sustain a higher pace. Over shorter distances I can manage around 7.2km/h (2m/s) though this is a limiting speed for me (can’t manage longer stride or faster cadence with a normal walking motion).
The additional energy of climbing is around 2x the net work involved at shallow slopes, increasing to around 5x the net work on very steep uphill slopes. For downhill walking, the relief in effort is never more than 2/3 the nominal effort of flat walking. The overall increase of effort for a steep circular route (i.e. ascent = descent) is seldom more than 10% over the same flat course. If there is interest I could supply the empirical formulae that I use for my own planning purposes. Generally work done in ‘flat’ walking is around 1 Cal per kg per mile, for a person of height around 5’6" ~ scaling inversely with height. There are published documents that indicate energy use in hill walking and running, which can be easily combined to give comprehensive work/effort analysis (I use for both planning and post-effort analysis).
Walking with load awkwardly held in arms is significantly slower, and additionally cannot be sustained as long as evenly loaded weight on shoulders or back. A Bindle is a comfortable way of carrying modest loads, and the staff could double as an aid in difficult terrain, or as an improvised weapon.