Who has the best advice on the best itinerary seeing Bernese Oberland with the B.O Pass in 7 days?

And the best laid plans are interrupted by Mother Nature and her wicked sense of humor....

Since you’ll be based in Wengen, I would just make a list of the things you’d like to see and do and when you get there you can decide what to do each day based on what the weather will be. There’s no need to make any advance reservations for anything, so you can be flexible.

Your planning is going to be contingent upon how much you want to walk or hike versus just go to places and to see them.

How many miles or kilometers will you choose to walk in a day? Are you comfortable with rougher hiking trails, or would you rather stay on smoother flatter terrain?

To Carrie's point, in Wengen you are quite central to most of the places you'll want to visit in the Berner Oberland. You can get everywhere fairly efficiently and quickly. But weather will make a big difference. You won't want to go to view spots if it is cloudy.

So a list of what you want to do and/or see is more helpful than a date specific itinerary.

the best practice is get up early to catch the first ascent anywhere to avoid the after breakfast tour group crowds; moreover it is clearer early in the morning; All decisions on what to do on a given day should be made the evening before or the day of based on weather forecasts and webcams which most sites have.

Noting for the day you go to Schilthorn (start as early as possible). the route from Wengen takes you to Lauterbrunnen by train, easy bus to Stechelberg. The gondola from Stechelberg goes through changes at Gimmelwald, then Mürren, and on upwards to the Schilthorn. So, on the way down, you can stop and cover Mürren and Gimmelwald in that one trip.

It all sounds so remote and distant, but the reality is that you can see most of these places from each other. It's just the mountain makes it difficult to from one to the other.

How early do the cable cars in Murren/Wengen begin running in June? (What does "as early as possible" mean)

What does "as early as possible" mean

Well, you probably don’t want to be out if it’s still dark outside. 😊 You can check the SBB schedule for times. I would plan to take the first available cable car up to Schilthorn at 7:25 from stechelberg to avoid the crowds.

https://schilthorn.ch/en/Infos/Timetable__and__Tariff

the best practice is get up early to catch the first ascent anywhere
to avoid the after breakfast tour group crowds; moreover it is clearer
early in the morning; All decisions on what to do on a given day
should be made the evening before or the day of based on weather
forecasts and webcams which most sites have.

Yep. Up and out early is a universal mountains best practice!

We wont be hiking

That creates a lot of flexibility for you in a day then! Hiking is awesome but gobbles up time and once you start its hard to bail out on a whim.

Two less obvious suggestions (among many great things to do):

The cemetery at the town church in Grindelwald is beautiful. The typical gorgeously planted, meticulously kept graves. But many of them are of locals who died mountaineering. So many of them! These graves are decorated with headstones and artifacts in mountaineering themes. Really very cool to experience standing there just across from the towering peaks. It's a compelling dissonance to look up at those giant mountains and then down at the graves of people who died climbing them.

And in Wengen itself, not far by foot on the outskirts, are some public barbecue areas. They feel like campsites set up in pretty places, but no place for camping, just some simple seating and big wood burning barbecues, and the wood supplied there by the municipality. It is delightful to pick up something easy to grill (sausages work great) at the COOP grocery store and stroll out for a pretty, comfortable picnic. Google Wengen Grillplatz or Feuerstelle. Not just Wengen, down in the valley, out in Murren - I think the Swiss have these things all over the place.

I know I shouldn’t say this, because to each their own, but I can’t help myself. If you’re going to the berner oberland, but won’t be hiking, that’s like going on vacation in NYC but not going to any museums. At least do a nice stroll through Lauterbrunnen valley or the north face trail in Murren. It’s fine for all abilities. Hiking in the berner oberland is one of the only things that lets you escape the crowds. If you can’t hike due to health/other reasons than that you just don’t care to, I am so sorry for my insensitivity. In terms of overall itinerary, I think there are better places in Switzerland where you’ll get more bang for your buck, such as Zurich, bern and Lucerne, if hiking isn’t your thing. In case itinerary switches are an option for you.

Hiking isn’t your thing so there are a lot of great scenic rides. As others have said, so much is weather dependent, but assuming great/acceptable weather, I’d organize my days be geography as follows, but not necessarily in this order.

1. A day on the Mürren side of the valley. Train from Wengen to Lauterbrunnen, bus to Stechelberg, gondola to
   Schilthorn/Piz Gloria, return to Mürren, lunch in Mürren and time in the village, mountain train to Grütschalp, gondola down to Lauterbrunnen and back “home” to Wengen.

2. A day at the Ballenberg Open Air Museum https://ballenberg.ch/en/. This involves a trip to the far side of Lake Brienz and is a good day trip.

3. A day in Grindelwald. Train down to Lauterbrunnen from Wengen, train to Grindelwald, wander the village, gondola up to First for lunch in the terrace and a look around. Return to Grindelwald and depending on the time you want to spend, consider riding up to Eigergletscher on the fabulous new gondola. Return to Wengen via trains through Lauterbrunnen or the gondola up to Männlichen and another gondola down to Wengen.

4. Time in Wengen with a ride up to Männlichen for the views. You can combine this with riding down to Grindelwald in reverse of the above route.

5. A day in Interlaken for shopping, watching the paragliders, perhaps taking a cruise on Lake Brienz. You can simply cruise the lake or you can take the boat to Giessbach Falls and ride the funicular up to the hotel for a view of the falls and maybe for lunch.

6. Take a lunch cruise on Lake Thun. Train to Thun, catch the boat near lunch time (reservations recommended but not required in my experience) and enjoy the views while you dine. Shopping in Thun is nice.

7. A day in the city of Bern.

While you said you do not hike, there are many walks that don’t require technical skills at all. Walking one way through the valley, the Staubbachbänklii or the Mönchblick walks in Wengen, or the walk between Grütschalp and Mürren. Once you are there, these might seem like good options to check out.

Looks like my-Swiss-life and I were writing at the same moment. She has some great ideas, too!

Niederhorn? Not sure I’ve heard that mentioned here before. Sounds like something I need to research and add to my list. 😊

I have looked for easy strolls but was unsuccessful. Thank you for the advice

Even if you aren't interesting in bigger walks, you can walk around the flatter parts of all the towns, little strolls along lakefronts, little walks in the mountains near the lift stations. You don't have to do big walks to enjoy yourself :)

That said, even if you are "not walking," the area you are going to is oriented to walking. Short walks to transfer from rail stations to cable cars for instance. Car free villages we're the only way to get from A to B is to walk. A little bit of walking is required simply to be there.