Alp Itinerary help needed for 3.5 days in/out of zurich

Can I assume you are arriving by train at Zurich Hbf from elsewhere in Europe? I'd say go straight to Wengen for 3 nights and come back to Luzern for the last day and a night, then to Zurich airport for the flight home on the 15th.

If you want snow-covered peaks the best choice in July is 3 nights in Wengen or Muerren. Grindelwald is bigger and traffic heavy, Interlaken is meh, Lauterbrunnen, which we love, is in the valley. You'll have better views for your short stay from Wengen or Muerren. The local transport of mountain trains, gondolas, and chair lifts are great fun. Easy hiking from Maennlichen (starts at Wengen) to Kleine Scheidegg is one of the best anywhere.

Murren and Wengen is what you’re looking for.

Thank you for the replies!
Do i need to be concerned about weather in July in Murren or Lauterbrunnen- Meaning is it better to stay on valley floor in the event the mountains are fogged in etc and we can’t see a thing up in Murren.
Lastly if ok to stay at a high elevation, do you recommend Wengen or Murren?
Any suggestions on best places to stay with terrific breakfasts?
Thank you again to everyone who has replied

Muerren strikes me as having a bit more traditional Swiss feel. Wengen is more modern.
As regards to weather, sometimes you get the opposite effect. Fog fills the valleys, while it is clear at higher elevations. Predicting mountain weather is a bit of a fool's errand.

I've done this with my teens, many times. When each of my 3 turned 14 we'd be off to Lauterbrunnen or Murren, and they liked it so much they returned twice as adults.
You can get all the experiences you need by staying in Lauterbrunnen or Murren. Take a look at our favorite dozen hikes in the area, 11 of which are easy. If you click on my name you'll find the link to the maps and pics and descriptions.
Wengen is nice, but doesn't have as many trails around it. I'm 50/50 on Laut/Murren. Slightly better views at Murren, but clouded in a bit more.

Wife and I sat on the restaurant patio of the hotel Alpenruh in Murren having dinner as an enormous cloud rolled into the valley and fully covered. We love Murren and have spent s few days every summer for the last several years. We consider ourselves extremely lucky to have such experiences.

I can't thank everyone enough for all the help.
Lastly, what's the latest I should plan to land in Zurich in order to get to Murren before the last cable car?
Does it make more sense to pay 260CHF (expensive!) to be picked up from airport and driven directly to Murren?

No need for a private car. The last train to make it to Murren would be the 20:46 (8:46 pm) out of Zurich (Flughafen, airport). You would arrive in Murren at 11:55pm, though this would be via the cable car from Stechelberg. It would cost 97 CHF (about $97) full fare, each. Presumably you folks would get a half fare card or some pass and the (young?) teen would be free with a family card.

You can check the schedules yourself at sbb.ch/en
The fares given assume a half fare card.

Private driver is a waste of your money and robs you of the fun travels on the super efficient Swiss transport system. It’s really quite a feat of engineering especially when you get into the mountainous regions. Do take the trains all the way to Murren...sit back relax and look at the scenery. Hopefully your flight gets in early enough so you’ll have plenty of time to grab snacks for the train journey while you’re in the station.

You can see all Swiss train schedules at www.sbb.ch/en Your starting point will be Zürich Airport or Zurich Flughafen to Murren BLM.

even if you had a private driver - egad the cost!! - you couldn't get higher than Lauterbrunnen. No cars allowed either side of the valley above Lauterbrunnen. Cable car Stechelberg to Gimmelwald and up to Mürren or cable car Lauterbrunnen to train and up.

Or the other side, Wengen only reachable by cog railway.

I'd advise to use the train system. It will be faster than driving too.