Hi Andrew. I graduated from WWU, so been to LSP many times. Mostly day trips, but did camp there a few times. Hope you and the family like trains, because you're right next to the track.
Can walk down to the water. Has a nice big lawn for frisbee and what not and also a stage. Chuckanut is a cool drive.
Would like join you all, but we're heading to Oregon about that time.
Have fun!