Every time I try to generate path grids the Construction Set crashes. If I try to remove the grid that is already present, nothing happens. I am using the commands that only effect the active cell. Any help?

Yeah, it crashes. You have to manually create them.

It only crashes in interiors though, impossible to create a pathgrid there since the CS can't know where the floor is. In exteriors it should work though.

True, but it should only be used in custom made exteriors, and not vanilla exteriors.

Okay well that makes sense. So I have to make my own grid? I have searched for some tutorials/extra information, and have found very little. From what I understand looking at Bethesda maps, I should map a "typical" route, not every place an NPC can walk? NPCs can navigate areas that are sparse on nodes?

Do you have any suggestions for good guides?

Path grids are covered quite well in these http://tesalliance.org/forums/index.php?/forum/12-construction-set-basics/ on TES Alliance.

Consider using CSE - It fixes many such crashes, including the one you mentioned.