I did the 24-day Spirit of Europe in July/Aug (2010) and it was one of the best times of my life. Comprehensive with what you see, just long enough before going crazy, and a mix of accommodation. It’s the best all-round trip I reckon. Hope that helps!
I’ve heard so many good things about all the trips!!! I haven’t booked it yet, but I’m planning on going on the Euro Odyssey starting on June 11-28.
I am also travelling solo in april/may. I am doing the dawn service and then onto doing the Eastern Spirit which is a part Spirit of Europe. These tours both finish in London and I cannot wait. Hope you find the trip that suits you best.