Does this mean it includes a train from the center to the St Pierre de Corps (which I believe it must go thru) to Paris? Seems like an important detail to find out before traveling. Anybody? Thanks!
Not necessarily. There are a few TGV's every day departing from Tours station, stopping at St Pierre des Corps, and then on to Paris Montparnasse. Or there are some TER trains going to Paris Austerlitz, also stopping at SPdC.
A reserved ticket should show arrival and departure time. If it doesn't reflect a connection at St P, then it should be a direct train. Direct TGV trains to Paris depart Tours roughly at 8, 12, 15:20 and 17:30.
The DB link at How to Look Up Train Schedules Online gives you good train schedules for Europe (but doesn't sell French tickets).
Thanks for clarifying!