Blind run of the one-puzzle sample, screen only, no printing, about seven minutes. I got the right place and the right digit on my own and both matched page 2. Not posting the answer since you asked for spoiler marks, but the walk checks out.
What I thought I had to do: sort the route notes by time, walk a coordinate grid from the night post, read the digit at the last square. That landed in one read. "Use the number at your final square, not a count of moves" did real work. I did not have to guess which number you wanted, which is unusual.
The one place I hesitated, and it is the only one: which way the rows run. "North is up" is right, but on screen the only clue to whether row 1 is the front or the back of the grid is where A1 sits relative to A4 in the layout. On paper you see it. On a screen you are reading the text layer and I spent a minute on "is A1 the bottom row", then worked it out from the night post being the near corner. Two words kill it: "row 1 is the bottom row." Cheap, and it is the kind of thing only a screen reader hits, so your printers will never report it.
Hints: none. The sample has nothing to hint with. I stopped at the end of the sample, which is where you asked.
Rewarding: the sort is real work and a wrong order punishes you immediately at the next step. That is what makes a route puzzle worth doing instead of a reading exercise. Busywork: nothing in the sample. The thing to watch in the other five is repetition. If two more of the six are also "sort, then walk", the second one will feel like admin. The ledger, stamps, weights and telegram sound like four different muscles, so I suspect you are fine.
Print note, since archivetrail raised alignment: the sample prints A4 in the corner but never says print at 100%. The 50 mm guide is in the full briefing, not in the sample, so anyone printing only the sample has nothing to check scale against. This puzzle does not care about scale. If any of the later records uses an overlay, a sleeve or a ruler, put the scale line on that page, not in the briefing.
Would I choose another paper adventure like this: yes. Discount that a little, I write tabletop one-shots for a living. The 12+ guess reads right to me. The difficulty here is reading load, not logic.
Disclosure so you can weigh the above: I have a free D&D horror one-shot on itch too. Not looking for a trade. If the full edition still wants another independent report I will run it and give you notes in this same shape, spoilers marked.