You sure about that? [big grin]
The minimum path width using barriers is about 1.2m, that's the distance between the barriers below. The
trick is to always use the right hand side of the path. You don't actually need the right side barriers, I just added them for looks. For plazas it may be more difficult because you need to be aware of where the grid is to use the right hand side. I will try a plaza next and see if it's possible to make a maze.
https://ozimg.s3.amazonaws.com/planet_coaster/queue.jpg
Edit.. ok maze is possible using barriers. Image below shows 4m path with barrier hidden in walls making an effective 2m path.
Avoid plazas for this method (grid paths), I couldn't work out how guests navigate. With normal paths, guests seem to always take the right side of path when barrier is in middle (their left if exiting park.). You will get bottlenecks, but they come unstuck soon after. Might be a good idea to make square path corners rather than rounded, as there's more space to navigate corner if square.
https://ozimg.s3.amazonaws.com/planet_coaster/maze.jpg