About your Brussels-Tours trip, I played around with the German rail site and found that there is a direct TGV train from Brussels to St-Pierre-des-Corps just outside Tours. You can consider that your arrival point in Tours or take a 5-minute local train to the central Tours station. This would save you from changing stations in Paris. It leaves Brussels Midi Station at 7.04 a.m.; check if it runs the day you want to go.

Andrew Missouri