<<"Any comments on the plan in Switzerland :) will be helpful . ">>
We have talked about your long day on the scenic trains.
We have not talked much about the Lake Lucerne area. We always stay there when we return to Switzerland, because the area is beautiful, and there is a lot to do and see. The attractions are varied and offer a rich selection for almost any interest. There are various mountains visible from the city or nearby by train (Titlis). Museums; the old city, nice walks, lake boats, etc....
We have no trouble spending a week in the area, and then do different things in the area on our next trip.
So, with that perspective, I and the forum moderators always suggest Luzern as a particularly good place to visit for the first time visitor to Switzerland.
On the other hand, if someone wants to go to Zürich, I ask them why? There are many good reasons to visit Zürich, but , for me they are cultural not scenic. In fact, it is my favorite city in Switzerland, but that is not for major tourist attractions. So, do you know why you want to explore Zürich?
What are your interests with your diverse ages?
So, to talk about your last day or so - including or near to Zürich - becomes a matter of very subjective and personal interests.
Certainly, a walk through the old town on both sides of the river is interesting. Find your way to the Lindenhof, for a nice view of the river and the city.
However, for some other things in the area, personal preferences play a strong role for me. For example - the Rhine Falls are a favorite place for many visitors. We went there once and would not do it again. However, our own history helps explain that. We have seen Niagara Falls here on our border of the USA with Canada, and even though the Rhine Falls are powerful, they do not impress us as much as Niagara does. So, I cannot offer a balanced opinion about the Rhine Falls.
If I had time to spare in that area, I'd consider Stein am Rhein (but not on a a weekend, when the tourists are excessively evident). If I had time, and my kids were patient with me, I'd go all the way to St. Gall and visit the Abbey and the library.
I'd take the train up to Uetliberg, above Zürich, make the short climb to Uto-Kulm and eat at the nice but not cheap restaurant looking out over Zürich. Then, I'd walk to Felsenegg and ride the self -service cable car (Swiss coins required) down to Adliswil and catch a train back to Zürich. Or, I'd stop at the mountain inn at Uto-Staffel about 600 meters along the trail to Felsenegg and eat there. Splendid views.
Personally, I'd stay in Luzern or on Lake Lucerne near a train station, and go to Zürich at the last minute. If I were to stay near Zürich airport, depending very much on my flight time, I'd almost surely stay in downtown Zürich, not at the airport. More choices for where to eat, and to take a short stroll around the town or along the lakeside. There are anywhere from 5 to 10 trains per hour from Zürich main station to the airport, and there are luggage lockers at the station, as well as a left luggage office. I might ship my heavy bags to the airport on the day before I leave. I'd avoid a cab unless I had good reasons to use one - the short ride costs 65 CHF, or more if traffic is heavy.
So, perhaps you have asked the wrong person about the last part of your trip. ;-)