Good point Susan,
When I took my 14 yr old son to Europe, and then on a seperate trip my 12 yr old daughter, I had each one of them do some research and come up with at least 3 sites THEY wanted to see.It really helped make the trips fun, and not just me dragging them around.
I also taught each of them how to use the metro and got them to look for signs etc .. to help me out.
Of course son found the Catacombs in Paris, which for someone like me ( claustrophobic) is not fun, but the deal was he came along to sights I was interested in , so I went to visit his! LOL
I am glad you have cut the trip down to 3 countries, you will do and see so much as it is, easier to keep memories clear if you haven't visited like 15 cities !!
Which three countries did you settle on?
Switzerland is amazing( although very expensive) there is nothing as pretty as the Alps.
I personally would skip the Benelux countries, but thats personal tastes. I have been to Luxebourg and can't recall anything about it,, thats never a good sign, LOL
How are you travelling between countries. I found it was cheap to fly from Paris to Rome on an Europeon airline, flew Air Vueling and it was cheaper then a train ticket ( when booked ahead)
Travelling with your boys will be great.