Hi luv2travel,
I remember my first trip to Europe, I went independently to London and caught the Eurostar to Paris, it was my dream come true also and I remember wanting to research everything. I was unable to see Versailles on my first visit and that was my excuse to return
To answer your first question, No I have not done the Moulin Rouge, it is not only too expensive for me but not really the sort of entertainment I like. But I truly LOVE Paris. People on my last tour to Paris liked it very much, so if you like that sort of thing then you should consider going. The weather in April will be nice, (Paris gets snow in winter and high 30's in summer), you will just need a jacket for the evening, especially on the illuminations tour, which you MUST do.
I have been to every city on your tour except Prague and have been to Amsterdam but not Brussels. Any other questions please just ask, I am more than happy to help. It is a bit frustrating not to have the optionals listed yet, but at least you have last years to give you an idea, and they don't usually change much.
Enjoy your planning
