Plot and Publish Log File Location
Specifies the path for the log file that is created if you select the Automatically Save Plot and Publish Log option on the Plot and Publish tab shown below.
I actually suggest that you turn this off on the Plot Tab.
TIP: If you turn this on – the file can get quite large.
Temporary Drawing File Location
Specifies the location to store temporary files. AutoCAD creates temporary files and then deletes them when you exit the program. The folder you specify must not be write-protected.
The TEMPPREFIX system variable (read-only) stores the current location of temporary drawing files.
TIP: I would suggest creating a special location for these files. Then when you crash you can delete all of the files with no worries. Something like C:/Temp
Temporary External Reference File Location
Specifies the location of external reference (xref) files. This location is used for the copy of the xref when you select Enabled with Copy in the Demand Load Xrefs list on the Open and Save tab. (XLOADPATH system variable).
If you select Enabled with Copy (which you should) on the Open and Save tab in the Demand Load Xrefs section, you’ll need a location for the copies of the XREF files. This value is also stored in the XLOADPATH variable.
TIP: you can set this to the same place as the TEMP files. How about C:/Temp