First off you can avoid the $3 fee ( every little bit helps ) by using certain passes:  "...An Interagency Annual Pass (old Golden Eagle), Senior Pass (old Golden Age), or Access Pass, Federal Duck Stamp, or an Annual Refuge Pass will admit the pass holder and 3 additional adults (over age 16). Children 16 and under enter free. Each of these passes are available for purchase at the Nisqually National Wildlife Refuge Administration Office and Visitor Center. All proceeds from entrance fees and passes go back into Nisqually NWR programs."  -from their official website.

This is a place for all ages and skill levels as its all flat. With that in mind, there are some parts that are gravel.  not all of this are boardwalks.  Also we came across one section of boardwalk that was closed.  but it did not look like a large section.   We saw many different species of ducks ( some that where white and black ).  A couple Heron.  One that caught a frog and was eating it.  Also we caught site of some doe's.  We saw an eagle on the driver over ;)   We swore we saw a bird of some sort  resting on top of the dead tree or post.  By the time we all took pics they showed nothing hahaha.

    We walked around maybe 70% of the area.  The one we did not get to was what seemed to be the main attraction.  where you walk out onto a mile long boardwalk and at the end have a 360 D. view  and special treats when the tide is out. 

    We will be back with more people around spring when there is more wild life !

Happy wild life watching :)