Switzerland and then northern Italy (my initial post disappeared?!)

Yes, I think your order is pretty good.
Instead of Wengen I would stay in Grindelwald with that amount of time. We rented a floor in a chalet -
Chalet Perle there, magical! Another couple was traveling with us so we each a bedroom and used the extra tiny bedroom for our luggage.
We enjoyed Lake Garda and drove up to the Dolomites on the west side of Lake Garda, stayed in Salò, and drove down from the Dolomites on east side of lake, stayed in Malcesine.
In the Dolomites we stayed in Ortisei and loved our hotel- Hotel Ortisei. We left our car in their garage the whole stay and walked to town and to the lifts up to the mountain valleys above.
We have spent a lot of time in Venice, once for two weeks. We have stayed all over Venice, liked the neighborhoods of Cannaregio and Dorsoduro best.

Here is your original post with several answers. So people can expand on that and not duplicate.

https://community.ricksteves.com/travel-forum/switzerland/northern-italy-then-switzerland

But the one posted earlier today died, as evidenced by the picture of Rick playing dead on the floor.

Pat posted Luzern to Wengen to Pontresina, Bernina Express to Tirano to Varenna to Venice.

I commented 2 options

1. Go to Wengen from the airport first as it is only 2 more hours on a train. Then to Luzern, because it is easier to get to Pontresina from Luzern than Wengen.
2. Keep Pat's itinerary, and if scenic railway journeys are your (or your husband's) thing, go Wengen to Spiez to Brig and get the Glacier Express to Samedan and change to short connector train to Pontresina. It is a long day, but the GE is relaxing with great scenery and good on-board services.

For Lake Garda, I recommend Nago Torbole at the north end (by Riva del Garda). We stayed at the Hotel Lago Di Garda with a huge deck and a private hot tub looking at AMAZING views. I understand there are many gorgeous spots around Lake Garda, and we hadn't planned to go there on our way to the Dolomites, but then I saw this hotel and I couldn't not fit it in.

All your Switzerland plans sound fine. I'd take a couple of days from Wengen (or wherever in BO) and add it to Lugano, but that's me

A week in the Wengen/Lauterbrunnen/Mürren area is not too long! There are plenty of easy and scenic hikes. You can day trip over to Grindelwald one day but basing in the Lauterbrunnen Valley give you access, IMO, to more options. We are staying in Wengen now for the first time. We usually stay in Lauterbrunnen itself. I am weary of the train ride up and down from Wengen every day for what will be a total of 12 days, but it is remarkably silent up here whereas in Lauterbrunnen and coming and going is more efficient it there is some noise.

Do try to give the Dolomites the full 5 nights and do stay in the mountains, perhaps Ortisei, Selva, or S. Cristina, not Bolzano nor Castelrotto. Ortisei is so nice because you can do so much from that base using the free bus pass you will get from your lodging.

We did an AirBnB in Malcesine right near the port. Keep in mind that there is only train access to the southern most point of the lake. From there to the northern end is about a 5 hour ferry ride. There may be faster runs at different day parts and seasons. But getting around Garda proper really requires a car. And keep in mind that during high season traffic comes to a crawl in many sections. Travel around Lake Como is much easier, especially from the eastern shore as this has rail access as well as ferry access. Bus service around the western shore is pretty good. Traveling by bus around the peninsula is not as convenient.

The post above caught my attention for a challenge that my wife and I have. We will be staying in Lauderbruten this September from the 19th to the 21st. Our next planned destination is Parma for three nights and then on to florence for five days before flying home to the U.S. I could use some advice on the best way to travel from Lauderbruten to Parma. Are there fast or scenic trains available? Seems like 7 hours and three changes is the best I can find right now. Advice greatly welcomed!

And 3 changes is the best you will ever find. Any scenic routing will add more changes and more time.

Mike S. Lauterbrunnen to northern Italy takes time! We tend to just devote the day to the transfer and make the most of it.

But it can be done in less then 5 hours with 3 changes.

Thanks to all that replied! Regarding our itinerary, we learned from other travel that it is much more satisfying to move around less and immerse ourselves more deeply, in fewer stops. One more question; I see that train schedules have not been released in either Switzerland or Italy for September travel. Any idea when that typiccally would take place. Thanks again!!!