Really great trails for kids. We took ours to Northwest Trek then did the nature trails. A great way to spend the day. We had our youngest in a jogging stroller, and it was bumpy but made it through just fine. Definitely more of a nature walk though than a hike. Only downer is I don't think you can do the nature trails without paying for the Trek.
Really pretty trail, even though most of the best views of Ohop Lake and the Sweetwater Spring were overgrown. Not knowing how the trails were and wanting to stay cool in the unusually warm weather we wore shorts and were greeted by plenty of nettle stings on the back portion of the trail, so beware. We did the entire loop around Sweetwater Spring and a few of the other random loops which ended up being a little more than 5 miles.