I created a generic map from the IA in a 4:7 ratio to use as a base for a trace.

Here is the image that I used Handdraw Fantasy for in a size of 400x700 (I don't remember if it's metric or imperial), for the purpose that I used the map, it doesn't matter either.

In this small example, I've separated them into even more sizes, adding an extra, even larger, fifth line.

Note a small detail: in topic 2, among the standard-size trees, there are some smaller trees. Compared to the others, where only the standard size is present, it gives a more "organic" and realistic appearance, at least to me.

Trees behind and in front of the hills also contribute to a more harmonious view.

To add more depth to the image, I suggest considering establishing 3 or 4 regions in the image (at least I usually do this) where the icons change size, each time a little larger.

To avoid getting lost, I usually leave an example of the size outside the map as a reference if I need to go back to work on a previous area.

Hey Royal, why don't you use a "water" sheet over the images to cover this passage and turn it into a waterfall?

After some tweaks with the storyteller, here is the final result.