Help: Which Eurail pass or train/flight combo?

What month is the trip? How long is your time in Switzerland?

If it fits your stay, a Swiss Travel Pass gives you maximum coverage there (and gets you to Chamonix) for $220 in 2nd class for 3 consecutive days or $263 for 4 consecutive. Advance-discount TGV tickets booked up to 4 months ahead from Lyon to Nice can cost as low as 37 euros per person. Chamonix-Lyon costs 44 euros (no advance discount). I would consider this combo, if the timing is right.

The France-Switzerland pass for 4 days of travel together currently costs $271 per person in 2nd class. With the pass, we recommend that you book Lyon-Nice TGV reservations at the same time that you buy the pass, since the number of places for pass holders is limited on TGV. You need not use TGV between Chamonix and Lyon and don't need reservations for your Swiss trains, either. The pass gives some transport discounts during your stay in Muerren, but not as many.

Thank you for the helpful advice! We are going in May. Our travel days will probably be the following: 7th, 10th, 12th, 14th, 17th, and 19th.

A Eurail pass is rarely a good idea. I would guess (though you would have to double-check the prices yourself) that individual tickets for each journey would be cheaper. Perhaps a local pass for the Mürren area if you are planning to use a lot of the mountain railways. Look on www.sbb.ch for Switzerland and www.sncf.fr or https://www.capitainetrain.com for France.

• Zürich to Mürren costs CHF 96 per person second class single.
• Mürren to Chamonix costs CHF 97 per person second class single.

To me it doesn't make sense to do the Nice-Zürich trip split between train and plane. That is inefficient. Nice to Milan is 4-5 hours, then you have to get out to the airport at Milan. You could either do train all the way (change at Milan and possibly other places). Or, better EasyJet flies Nice to Basel (1½ hours from Zürich), and Swiss flies Nice-Zürich. Swiss can be cheap if booked far enough in advance.

I assume you're going to stop and see Milan. If not, then Chris's other flight suggestions make sense.

If you travel Zurich-Muerren on the 7th and Muerren-Chamonix on the 10th, then the 4-day consecutive Swiss Travel Pass is the one that fits that window. The pass may or may not save money versus the separate train tickets, depending on how many other trains/buses/boats/lifts you use during your stay. Even if you just break even, it gives you hop-on convenience as far up the mountains as Muerren on one side and Wengen on the other.

For travel in May, now is the time to book TGV tickets at the best rates, with limited seats at these prices.

Thanks to both of you for your input! I am still researching to get this right. :)