Dazed and Confused by public transportation

If you'll be staying in that area only, you may want to look into the Bernese Oberland Regional Pass: https://www.regionalpass-berneroberland.ch/en/

Yes, the Berner Oberland Pass is the "local" option. It has slightly better coverage of the mountain railways and cable cars than does the Swiss Pass.
If you get a Swiss Pass, you then only need to buy tickets from Innsbruck to the Swiss border (Buchs (SG)), and from the Swiss border (St Margrethen) to Munich
If you get a Berner Oberland Pass, you will need to buy tickets from Innsbruck to Bern (Where the coverage for the Berner Oberland Pass starts), and from Bern to Munich.

You might find that it is cheaper to buy train-specific nonrefundable tickets many months in advance to and from Lauterbrunnen from Outside of Switzerland. Example: Lauterbrunnen to Munich can be as low as 39.90 EUR when you buy them from Deutsche Bahn. SBB, the Swiss rail company will charge more than that just to go from Bern to St Margrethen.

You can always buy individual tickets for each ride while in Switzerland. Depending on how many trips and where, it could be less than the cost of a pass. Swiss price passes like you are going to do a huge amount of traveling. They often don't provide savings. You are paying a premium for convenience.

The Berner Oberland Regional Pass might be a good option in this case, however as I recall it has specific validity periods (ie: May to October). It may not be an option in April.

I'll try to provide more details when I have access to a "normal" computer.

According to the FAQ's for the Berner Oberland Regional Pass for 2018.....

"Is the Regional Pass also available in winter?
No, the Regional Pass is only available from the end of April until the end of October."

dazed & confused,

You may also find this website very helpful.....

https://www.ricksteves.com/travel-tips/transportation/trains/switzerland-rail-passes

Unfortunately the question of which rail pass to buy for Switzerland is difficult for many travellers. In the past I've resorted to using an Excel spreadsheet to compare the costs of various passes vs P-P tickets. You'll have to crunch the numbers to determine which combination of pass and tickets will work best in your situation. The Half Fare Card is often a good solution for many.

I would look at what is included with each pass. The hard/frustrating aspect of the passes is that you won't know exactly what you want to do until you are there. The weather can really impact your choices. The Swiss Travel Pass does include the trip up to Schilthorn. I stayed in the Lauterbrunnen valley and because of the weather and other factors, we found ourselves up and down from Lauterbrunnen to Gimmelwald/Murren more than we expected which was fine for us because we had the travel pass. We adored Gimmelwald and I think in the four days we were in BO, we ended up there three times.

Bottom line is...if you buy the Swiss Travel Pass then you're home free once you cross the border into Switzerland. You just jump on any train any time you want. You can find schedules and connections at www.sbb.ch/en so that you'll know which Swiss train to catch and where to change, but if you can't figure it out then just ask at any ticket counter. But no matter - you won't ever have to purchase a train ticket in Switzerland if you have the STP and don't go above Wengen.

I want to thank each of you for taking the time to respond with insight and forethought.
With your suggestions in mind, it looks as if the SwissTravelPass is inevitably the best, if not only, choice for our trip in April.

Once again—thank you.