We walked with an 8 year old and a 6 year old. There is an unpaved path through the woods or you can also walk on the paved bike path. The unpaved path is shorter since it hugs the shoreline of the lake part of the way. We took the unpaved path and it was about a 15 minute walk. We spent some time at the petting zoo, explored the store and then took the boat back from FW to WL. The boats run about every 10 or 15 minutes and it is a very pleasant ride.
We have also rented bikes and ridden on the bike path. My guess is that it would take 20 - 25 minutes to walk on that path to FW.