Walkthroughs for custom maps.

By the way, ProspectorRT doesn't determine map traversability.

Yes, at least for now, it doesn't have that functionality: it can only show the correspondence between pairs of monoliths and dungeon gates. But it is useful because it accurately shows the presence of objects, artifacts, spells, skills, creatures, and heroes that can be obtained in some way (sometimes in a completely non-obvious way). I remember that on one (otherwise good) map, several years ago, I had to tediously "clear" individual areas on the advice of one player to find artifacts that were necessary (or rather, one of two) to complete the map, but they could not be found anywhere through direct search in the editor. It turned out: they were with monsters! And there were a lot of monsters on this map, and those 2 monsters were located far from all the paths that my hero traveled.
Fortunately, with the advent of Prospector, this is no longer a problem. But this fact does not negate the need for authors to think and, if necessary, give players advice or hints. Unfortunately, for some maps, even well-known ones, there is no information even about the authors, let alone their contacts. But sometimes: the author is known, and there is contact information, but the authors are in no hurry to fix errors, even when players directly write about them. This is the case with a couple of maps by respected sirs from HeroesPortal: after learning about the errors, they promised to fix them. 10 years have passed - the maps are still in the same state. At least there are comments, from which you can find out what surprises await you. Sometimes you fix some "mistakes" yourself (if the map looks decent overall).