We used to launch my buddies boat the day before and tie up to the docks that surround the launch area overnite when we used to fish the derbies. Had friends who used to do that on a regular basis on the weekends (Warfrats!) . Still see people sleeping overnite on their boats. Only problem was that the gates were locked at 10pm and you had to call the port security if you needed to get in after hours. I dont think it's changed any but you might try calling the port of everett as they manage the launch.