You should count on this backcountry hike taking about 9 hours, but of course some folks walk a bit slower and some a bit faster. Some parts of Cowlitz Trail are much higher up than other parts of the trail which of course means you need to be prepared for different conditions on different parts of the trail. Being 10.6 miles long; it's considered a longer trek. This is a one trailhead great outdoors hiking trail, so in and out is the way to backcountry hike it normally. Keep in mind that this is a long backcountry trail, so don't forget to pack enough supplies. Cowlitz Trail has a total elevation difference of 2,199 feet which is an average number.