Some books say that when Washington headed back to Mount Vernon, he deliberately left his slaves ('forgot them') in Philadelphia, so they would be free. If this is true, it should be mentioned.
It won't be!
I visited Philadelphia just a few months ago and took the tour of Independence Hall and visited Christ Church, sat in George Washington's pew, visited Ben Franklin's grave. The Park Service did a great job with the tour. Plenty of information, respectfully and fairly presented. I had a great time. I hope they do as good a job with this subject. It seems to me they are right to work it into the presentation. The key is to do a good job of it. Here's wishing them luck on their task.
PS-Mt. Vernon is next on my list of historical places to visit. Then Monticello. Then Montepelier. Then Quincy, Mass. etc etc etc. (if I live long enough--Lord willing)