I also have problems with the tour pathfinding algorithm.   There have been some other threads saying the same thing in a TPM Facebook group as well.

Sometimes creating the tour will show a strange path right off the bat, and sometimes I can get a good path to start, and then after some gameplay, it'll change.  I don't know what causes the game to remake the paths, but it may be either a change of staff (if someone goes on break), or if I upgrade one of the exhibits.

Once the game gives me an overly complicated path, deleting the tour and remaking it will not change the wrong path. I have to move one of the displays to "reset" the pathfinding.

I"ll upload four screenshots.   Two will show the path I started with, and then the next will show what the game changed it to after.  On one set of images, I did end up moving a rock decoration to see if that was the problem, but it kept the strange and overlong route.  I never bothered to move the decoration back though.  I reset it by changing the orientation of the footprint display, then changing it back.

I encounter this issue all the time. I have encoutered it on every map I have played so far so seems to be an issue with the pathfinding algorithm itself rather than any map- or scenario-specific cause. The pathfinding for the tour guide will veer wildly off course—most often in my games it appears to attempting to take the tour path through a completely unrelated doorway, for example: i can have a tour set up on one corner of the map, and the pathing for the tour will try to take the tour through a bathroom door on the complete opposite corner of the museum (this is not limited to bathroom doors, it will also try to path through unrelated plain doors, one-way doors, and themed doors). Rotating or relocating the tour stand ​occasionally helps, as does some rearranging of objects in the museum, or creating walls to cut off the pathing, but more often than not it will simply choose a different unrelated door to path to and double-back from.

[Video shows convoluted path in one museum, screenshots 1&2 show simple one-stop tour on the same map which desplays this behaviour even without crowded decorations, screenshot 3 shows this behaviour on a different map]