If you are staying in Kennewick off 395 or near the East end of Kennewick the 395 exit off of 182 will be closed during the NCT weekend just to make it difficult on everyone.
I have attached a google maps with a detour to get you back to 395 in kennewick from the track.
http://maps.google.com/maps?f=d&sour...,0.699692&z=11