For Dallas however I opted to take him to the Mukilteo Lighthouse Park. It is located close to the ferry terminal which takes you across to Whidbey Island, another excellent place to visit in the area. There are many lighthouses to be found in the Puget Sound region and I suggest you seek them out. If you'd like to tour inside one do check ahead of time as many have limited visiting hours. Lighthouses of Washington is a great guidebook to all the lighthouses in the area. If you decide to take the ferry over to Whidbey make sure to check out the Admiralty Head Lighthouse as well!
Grab some fish and chips at the Ivars Fish Bar and have a little picnic on the beach like we did. (We actually grabbed our fish and chips up from a little place in Everett that I can't recall the name of but Ivars would do the trick.)
Make sure you take the time to stroll along the beach looking for
or starfish skin (aka sea kelp),
skipping rocks, walking along the driftwood, and hunting out abandoned forts!