Thank you! This sort of graph is actually easy to do in Inkscape:
Use the “calligraphy” tool for lines; default configs, quick strokes. If the stroke gets slightly off it’s OK, but if it’s really off simply redraw it (easier than trying to fix it). The dashed lines are simply sequences of lines using the same tool.
For the text plenty cursive fonts work fine; I used First-Grader, but Lehn183, Berenice, and even Comic Sans would be good options.
Red background: I found easier to start with a larger-than-necessary rectangle, and then shave it off by subtracting copies of other elements.
If any object is a bit too detailed, or has rough edges, a few hits of the “simplify” tool (Ctrl+L) fixes it.
Thank you! This sort of graph is actually easy to do in Inkscape: