Per an earlier post I checked the SNCF site directly for tickets ... but when I went to actually make tickets I just got routed to Rail Europe anyway .... I ended up buying first class TGV point to point tickets between Paris and the starting/ending points of our cruise (Chalon and Avignon, respectively) via Rail Europe instead of passes ... This ended up being about $100 cheaper (than a 3 day pass) With the passes you first pay for the pass, then you need to make additional ($10 each) reservations for each trip.

With the point-to-point tickets the reservations are included; you can do your tickets/reservations up to 90 days in advance (and change them for free up to a day or so before the trip) ... so if you know where and when you want to go when it is best to make them early as reservations get harder to get the closer you get to the date and (per the RailEurope web site, 1st class reservations are limited for pass holders).

I don't know if you would call it a good thing (especially if you are a 'free spirit' traveler... as I would like to be, but am not)..but having to catch specific planes and boats makes it easy to know where you have to be when; if we were not tied to specific schedules I'd love to just get a rail pass and go in the direction of the whim of the day...maybe the next trip.