The trail starts off easy and smooth, but after about 3 miles it gets quite a bit rougher, more technical, and more challenge. This more technical portion of the trail continues for an additional 8 miles. However, the route mapped here turns around at Alpine Road instead, for a simple 10-mile out-and-back route.

Beyond Alpine Road, not only is the trail continuously rough, but it's much less maintained than the first 5 or so miles. But if you're in for an adventure, continue on!

Since the North Fork trail is at such a low elevation, it stays accessible and snow-free most of the year. While conditions can get wet in the winter, the rocky trail bed drains very well, making it a popular escape for locals even during the depths of winter.

Sources: https://www.outdoorproject.com/articles/mountain-biking-oakridges-north-fork-trail https://ridespots.com/rides/middle-fork-willametter-oakridge-oregon-mountain-bike-ride/ https://www.alltrails.com/trail/us/oregon/north-fork-middle-fork-willamette-river-trail