go to
www.raileurope.com
You will find all the schedules, fares and you can prebook everything here in USA
Used them last year and they were fine
You are taking on too much in such a short period of time
FYI for Madrid to Paris on 12/25/08, the fare is US$124.00 and takes 13 hr 27 minutes
I might fly the MAD/Paris , the Paris/Venice and Rome /Barcelona segments and use train on the others