I appreciate everyones comments and suggestions.
With regard to the Eurail Pass, we are traveling beyond France, to include Germany and Switzerland. Have used this pass several times before, and on other trips have just bought tickets for a specific train. It just depends what we are looking for.
On this particular trip, the only trains that require a reservation, that we are taking will be Eurostar, and TGV to Strasbourg. Other than these two, we wanted to have the flexibility of the pass vs. being locked into a specific train for the remainder of the trip, recognizing that yes it may be cheaper to buy point to point. We will use a flex pass,(which in my mind is a reasonable cost if you hold it to a 4 or 5 day pass) and use it on the most expensive runs, and purchase remainder of tickets point to point, or utilize regional passes like the Bavarian Pass for example.
Back to the transfer between stations, if we choose to do this on the shorter connection, getting to the front of the train is an excellent idea. At this point I think I have a pretty decent idea about the route I would take Rue d Alsace, which includes some stairways, but you also enter into a side door of the station, directly at the train platforms.
We are still debating, but was wanted to get some other opinions, and we thank you all for that!