In July, my wife and I will be leaving a large musical tour and heading to Switzerland from Munich, where the tour ends. We want to spend several days in Lauterbrunnen, then we fly out of Zurich. Suggestions on the best Rail passes for this configuration, please?
If it's just those two trips, don't bother with rail passes. Just buy two single tickets.
For the Munich to Lauterbrunnen leg, if you purchase well in advance, you can get fares as low as 55,90€/per person with German Rail advance purchase Super SparPreis Europa tickets. That would be for a four change (Stuttgart, Zürich, Bern, Interlaken), 8H08 connection. A three change (Mannheim, Basel, Interlaken) connection. about 7H57 would cost 61,90€.
Those fares are for Non-returnable, non-exchangeable tickets. For 8€/P more per ticket, you can get a ticket that is returnable with a penalty for a voucher for a different ticket. With the 8€ more SparPreis Ticket, you get a city ticket that would include any local transportation in Munich.
Those fares are not yet available on the Bahn website. Only June is bookable today. Even after next month, when the July fares are available, the fares will probably remain low for a while until the lowest fares start to sell out.
Get the Half-Fare card. Once in Lauterbrunnen you will want to take all the neat mountain lifts and trains to explore the valley. Those add up quickly.