Paris to La Rochelle & Vice Versa

Has anybody done the above trip by train? How complicated is it i.e. are there any train changeovers etc.

Take France's high-speed train known as the TGV. There is a direct train to La Rochelle from Paris's Montparnasse train station that takes about two and a half to three hours and costs between 60 and 80 euros for a full fare.
You can book train tickets online at www.tgv.com and then pick them up once in France.