Swiss Pass, Half Fare, etc.

It is easy to get confused, but no worries. We can help. A Swiss Pass covers train and boat travel to villages-like Wengen. For recreational lifts (sightseeing, hiking, skiing) it covers 50%. (Except the Jungfrau trip which is 25%). So it is not the case that it "doesn't work" past WEngen; it just doesn't cover 100% of the cost. There are some local passes, like the Berner Oberland Regional Pass that do cover at 100% some (but not all) of the lifts in the Wengen/Grindelwald region. This pass can be usful if the BO is your only destination in Switzerland, but it looks like you are going elsewhere, like Zermatt. To find fares, the map on the RS site just provides estimates. To see the actual route and fares, use the Swiss rail site, SBB,ch or rail.ch (same thing in English). Enter "Wengen" under From and "Zermatt" under To to see the fastest and most direct routes. If a price shows on the first page above each suggested route, be aware that is Half Fare: in other words, WITH a Half-Fare Card. You can just double that to get the correct fare for tickets w/o a card. If you post your planned itinerary it might be possible to guestimate what would be a good choice, but if you really want a definite answer then yes, you have to add up the cost of all your journeys. Trouble is, sometimes you don't know exactly what you want to do until you get there. In that case, just knowing what village-to-village travel you will be doing can help make the estimate.

Lola, that is the clearest and most concise summary I've seen. Thanks very much, that will help many more people than only the OP! The only thing I would add is that the Swiss Pass also covers urban transit systems and nearly every museum entry fee, which the Half Fare Card doesn't. That smaller stuff can add up too. The Half Fare Card does give 50% off on urban transit but doesn't cover any museum entry fees. Note this caveat from the sbb site: "Over short distances (because of minimum fare), on urban public transport systems, on reduced tickets or for some combined offers with additional services, the discount with a Half-Fare travelcard may be less than 50%". And then there's the Flexi-Pass, which is 100% coverage on pass days and 50% on non-pass days, with free museum entry only on pass days... Yes, it's complicated but worth thinking through since normal fares are pricy.

Realize that many train is Switzerland are privately owned and therefore expensive and also do not have fare agreements with other rail companies.
Hopefully you have a Rick Steves Switzerland guidebk that can help you get the missing info you need and websites that you need to reference.

Thanks so much for everyone's help. We really appreciate it!