Thanks for letting us know about your trip. I'm about 3 hours north of Long Beach and recovering from a little surgery, so I can't make it. Long Beach has done a lot of redevelopment around the convention center and the Aquarium of the Pacific. My favorite thing in the world is to tour aquariums all by myself, so I know what I'd be doing if it was my afternoon. The Queen Mary has nice views of Long Beach (it looks across to the conv ctr and aquarium) and is fairly well preserved-restored with lots of beautiful wood and art deco touches. They continuously change the arrangements, but it's typically been nominal or no fee to stroll on and get the run of most of the ship, then an extra charge of like $16 to go through the engine rooms and see some special exhibits like furnished cabins of each class and ship models - prob best enjoyed by the most obsessed.
Have a great trip!