Not worh the 4.5 hrs drive if your expecting DH runs. On the other hand if you want some good flowy XC/am trails then Kelso can be fun. An if you get board there you can always head upto Hilton falls which is only 10min from Kelso.
Hilton Falls, your source for trails with rocks, rocks and more rocks. Great place for a good full body work out when you keep the tempo up. Even if the elevation change is only about 25-30'.