this is more of a question but is there a fast way to place pathnodes? also fast way to make barriers?

indeed. select a pathnode (like any other brush, patch, etc.) and press "Space".
now you have two. You can repeat the process with two to get four and so on.
The same goes for barricades.

also max distance between node connections is 128 units.
you can select grid(in the top bar) and select grid 128, then copy the node and it will be copied 128 units away.
you can like this cover big areas faster and without wondering if the node will connect.