Railpass France/Switzerland ??

First of all there's 1 direct TGV daily from Paris to Interlaken. Just checked 9/6/16 randomly and that fare is 52E one way. Alternately you could just travel TGV->Basel and then travel leisurely on your own schedule on Swiss trains all the way to Interlaken.

Second, Swiss Rail Passes are generally a good buy...most commonly the Half Fare Card which gives you 50% discount everywhere all over Switzerland even to the expensive Jungfrau. If you take that trip the savings (just from that trip) practically pays for the HFC.

Lastly - don't stay in Interlaken. You came to see the Swiss Alps (I'm guessing) so choose a hotel IN the Swiss Alps in the alpine villages of Lauterbrunnen, Wengen or Murren. Lauterbrunnen is just an additional 20 minutes on the train from Interlaken Ost...and you must go to Lauterbrunnen to actually get into the alps. From the Lauterbrunnen Valey you'll pass through Wengen on toward the Jungfrau on one side of the valley or you'll pass through Murren on the other side of the valley going to the Schilthorn.

It should not be hard to get TGV reservations if you do it soon at https://ricksteves.raileurope.com/us/rail/point_to_point/triprequest.htm. On the direct Paris-Switzerland service by TGV Lyria, pass holder reservation prices are higher than any other train - $43 per person in 2nd class. Domestic TGVs to Strasbourg have $11 seat reservations but require an extra connection to reach Switzerland.

Connections within Switzerland don't require reservations, so if you choose a route that connects at Strasbourg or Basel, then don't request the reservation any further than that.

Thanks, Tim and Laura.

I did look at the one low-cost train but it arrives in Interlaken at nearly midnight, and the nearby hotels in my budget range close their desks at about 9 -- booked one (cancellable) wirh a note to management asking whether they could accomodate late check-in, but while waiting for a response the cheap train tickets disappeared. My original plan was to arrive in Interlaken mid-afternoon and make my way up to Murren, where I have reservations ( also cancellable.)

Still running the numbers and playing with alternative routings.

Interlaken to Mürren is only 20 minutes, so there's no reason to stop in Interlaken - just go all the way to Mürren when you arrive.

Right, Harold -- the only reason for considering a stop in Interlaken was if I was coming in at midnight, well after the transportation to Murren closes down. But since that seems to be off the table ...

Are you in Paris before leaving for Switzerland or are you just arriving in Paris and immediately turning around to get to Switzerland, Laura?

Nigel, we will be in Paris for a few days before leaving for Switzerland, then returning to France to do a week of Normandy-plus-Loire touring by car, finishing up in Paris again. Three weeks total.

In that case you can have a reasonably inexpensive TGV to Strasbourg, the TER to Basel and anything going from Basel to the Berner Oberland, save money in exchange for a slightly slower all over trip, and still get to Mürren or elsewhere in the Berner Oberland at a reasonable hour. No need to arrive late at night.

Point-to-point tickets have been bought, whether it's the best or not, it's DONE. After reviewing the trains through Strasbourg, I looked at Paris-Geneva and then found a direct Lyria to Lausanne at €44, which will connect with local trains to Interlaken, Lauterbrennen and Muerren.

Thanks to everyone for their input.

I am glad that you found the option you feel works for you.

Two clarifying points for purpose of the general discussion. You were quoted reservation fees for second class. Rail passes for adults are first class so the reservation fees might have been higher.
The type of rail pass you were describing doesn't work past Interlakken, although it does give you a discount on the tickets you buy from there on. You would still need to buy tickets for that portion of the trip.

The trip from Gare de Lyon to Lausanne is quite a nice one. I expect that will turn out to be a good decision for you.

Gare de Lyon has 2 sets of platforms, one is alphabetical and the other numerical. Be sure to go to the right part of the station.

Thanks for the info, Nigel.
Carol, actually the Global Eurailpass is first-class only, but the two-country France-Switzerland pass and other select passes offer a choice of first-class or second-class.