Spiez Switzerland Area Rural Travel Options

Don't know what the rest of your itinerary looks like, but I would suggest you make time on a weekday and rent a car for a day. There are rental locations in Interlaken.

Diemtigen is served by the train to Zweisimmen, which is covered by Eurail. But the busses are indeed not. And the bus and train services are integrated so normally from Bern you would buy a ticket to "Diemtigen" and it would include bus travel. That is just another reason why an Eurail Pass is not a good idea. I don't know if you have already purchased it, but you may want to reconsider it.

Now most of the houses in Diemtigen are now near the station od Oey - Diemtigen (which has trains at least every hour), but the Church and the Graveyard are indeed at the old village location. It turns out Diemtigen has three graveyards, and you didn't mention which one you want to visit. For the one near the church people would just walk. In this part of Switzerland funeral services usually start at the graveyard, where the urn is buried, and then afterwards there is sometimes a service in the Church. And I would expect everyone involved to just walk between the two places.

But 250 is indeed not very frequent. But in most countries such a sparcely populated area would not have any public transit at all.

Now I do not know what you expect to find when you visit that place. The Church will be a pretty standard Swiss Reformed Church. So plain, and so well looked after that it will look as if it was constructed just a few decades ago, not a few centuries. And the graveyard is not going to have any graves older than a few decades either. We don't keep graves around forever here. So don't expect to find any traces of your wife's ancestors.

If you want to experience a bit of the heritage of your ancestors a good thing to do is to walk (maybe part of) the Simmentaler House Trail. The Simmental is famous for its carpentry, and there are lots of old wooden historic farms in the area. That would give you a view in what your ancestors life might have been like.

https://lenk-simmental.ch/en/erlebnisse/simmental-home-trail-2/

Thank you very much for your informative and thoughtful reply. My wife's ancestors were married in the church. So, we are hoping to visit and see inside. The graveyard of most interest is the one farther away along the bus route. It still has family names buried there. My wife comes from the Hirschi and Wiedmer families both of Diemtigen. The only thing that I've been able to specifically identify where her ancestors would have been is the church where they were married.

Your link to the house walks is very, very interesting. We will definitely stop and see a few of those houses. There are several on the list right there in Diemtigen not far from the church. Wish we could find a Wiedmer or Hirschi home. But, I didn't see any with my quick review.

We do have our eurail passes because we will be in eastern Europe and Germany before coming to Switzerland.

Based on the input here, we are now rethinking our Swiss itinerary. We think a 1 day car rental might be appropriate. I think I will make a separate post with our full itinerary asking for thoughts on that as that presents several additional issues.

Thank you again!

Perusing google maps, I see a Wiedmer Shoe & Orthepedics store a short walk from Oey-Diemtigen train station.
https://www.google.com/maps/@46.6589959,7.5766698,3a,75y,212.58h,92.1t/data=!3m8!1e1!3m6!1sAF1QipMW5ovXFh6Mp3WQwAjWh980Y4yR9ZjmNAbsaKqS!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipMW5ovXFh6Mp3WQwAjWh980Y4yR9ZjmNAbsaKqS%3Dw203-h100-k-no-pi0-ya122.69852-ro0-fo100!7i7296!8i3648?entry=ttu

I don't know if the Restaurant Hirschen has anything to do with the Hirschi family (current owners have different name) but it looks very nice. Next to the church in Diemtigen Dorf. No credit cards!
https://www.hirschendiemtigen.ch/index.html

Thanks. I saw those names and a few others around the area. We have had other family go and said there are family names on graves, businesses, and similar. It will be fun just to see the area for sure.

"Hirschen" is a very common name for a restaurant. You als will find "Bären", "Steinbock" etc... And as you can guess, these are all names.

If you have a confirmation that there are still old graves on the graveyard (they usually get cleared here after 20 to 30 years) then yes, go and visit, and for that a rental for a day is indeed going to be useful.