Sounds almost exactly like my 8th grade trip, except for the monuments that weren't there in '83 ish.
I was only 13, and it was fine.
The ONLY problems I had were because I wasn't popular, and only the popular parents chaperoned, which meant I was looked over by them, and the infractions THEIR kids did were passed over.
The ONE thing that happened was that my buddy and I misheard instructions...we thought they said to meet at one museum, but they said another, so she and I were waiting at the art museum for ages until we finally figured out we had heard wrong. We were definitely on time, though!
So we started down the sidewalk, and found a cop, because that's just what you do. He had us get in his car, drove until we found our bus (we remembered the number), and got out! It all would have been simple, we did exactly the right thing, but one of the popular kids saw us and decided to say that he "found" us.
We got in trouble for "not listening"...well we were sitting in the back and everyone else was talking, and we THOUGHT we were listening, we both thought we were supposed to meet at the same museum the other did... We got to sit in the bus for Jefferson, and I thought, and still think, that that sucked. We weren't misbehaving and we got ourselves out of a possible mess by doing the right thing and keeping our heads. Harumph.
Other than that the trip was great, and I still have the big picture outside the capitol building.
(by the way, if DS were doing this trip with a school (unlikely, as are homeschooling), I would chaperone, just to try to protect the kids that aren't popular and might be overlooked. DS I'm sure would be an outgoing popular kid but others aren't like him (he got his extrovert side from hubby), and I would want to be there to make sure no one is railroaded by misunderstandings and biases against the less popular kids)