Coming from a local boy to all these who has spent a lot of time at them all, you are definitely overbooked for 2 weeks! You can spent 5 days in DC alone to do the Smithsonian and National monuments justice... Gettysburg is easily a long weekend. Baltimore can be a 2 day excursion to get the fort, aquarium, harbor, etc... Philadelphia is another you can spend a week in with all of the history, NYC even longer, and I could go on about each. I would encourage you to really look to focus your trip because you can make three 2 week trips with everything on your list will little effort!
Fort Delaware is fantastic! It's only a 40min drive from our home, and we frequently visit. If you going to see Fort Delaware (kids love the night ghost tours), then you also need to add visiting Fort Mifflin, Fort Mercer and Red Bank, and... Can you see where I'm going? Tons of history here!
Make it a focused trip and come back and see us a few times! Drop a PM if you need any campground recommendations in proximity to any of these destinations!