We're a month away from this trip, here's our itinerary:
Day 1: arrive Zurich mid-afternoon, pick up rental car, staying in Old Town Zurich
Day 2: drive to Innsbruck for lunch, then on to Krimml Falls for the night
Day 3: drive the Grossglocker High Alpine Road, slight detour to the Grossglocker glacier for lunch, then continuing to Cortina d'Ambrezzo via Tre Croci Pass. Question: need to buy a day pass to drive the High Alpine Road. The website says the pass must be used before its expiration date, but I can't find any reference to how long the pass is good for. If I purchase now, will it still be good in a month?
Day 5: drive to Alpe di Siusi (Seiser Alm) OR head west over Gardena Pass, then Sella Pass to Bolzano (which is a better route?). Then into Italy, crossing Stelvio Pass, through Parc Nazional Svizzer to St. Moritz.
Day 6: drive San Bernadino Pass to Bellinzona, then Lugano, ending the day in Menaggio.
Day 8: Menaggio to Stresa, Italy
Day 9: over Simplon Pass to Chaminox, France
Day 10: Chaminox to Annecy
Day 11: from Annecy to Geneva for lunch, then on to Lausanne and Montreaux (Chillon Castle)
Day 12: on to Interlaken (plans to drive Susten, Furka and Grimsel passes the next day)
Day 14: back to Zurich

Just fyi, my husband and I love driving trips and I hope that I have planned the length of each leg to not be too tiring and allow some stops along the route, but we are not big on spending time a sightseeing "tourist trap" venues, we prefer just to go at our own pace. Anyone have any input on these routes, especially preferred scenic drives to get us from point A to B?

Four hours day driving alpine roads each and every day is not for me. My own style would be far less time in the car and far more time out on foot even if that means I couldn't check off so many passes and villages from my must-see list. If I had it my way I'd stay in one location for a week and hike every day. But if that's the kind of trip you're looking for then I'd say you've nailed it.

If you really want to do that much driving then it's your call. I would make one minor tweak to your plan. Take the train into Zurich when you arrive and pick up the car at the train station the next day. That would be one less day you will pay on the rental and one less night of parking fees at the hotel.

As I said, we are very experienced at driving trips, been doing these for 25+ years. All of our airfare, car rental and hotels have been booked and paid six months ago. I'm just looking for insights into best scenic routes as we are finally closing in on our arrival in Zurich.

Can't offer any help with routes, but this is our kind of trip too. I hope you enjoy yourselves and the weather is kind to you.

thank you!

I suppose the main purpose of your trip is the drive and may be the landscape.
Therefore I don't mention all the scenic towns, castles churches, museums etc. along or close to your itinerary.
(Cortina -) Arabba - Bolzano:
fastest route: via Pordoj Pass - Karer Pass
most scenic route: via Gardena Pass (or Pordoj Pass - Sella Pass) - Ortisei - Alpe di Siusi.
Don't underestimate the many hairpins on Falzarego Pass, Pordoj Pass, Gardena Pass and Stelvio (Eastern ramp).Even if there are not too many dumb tourists running at extremely slow speeds, the journey will get incredibly long.
Therefore I don't mention more time consuming alternatives for this leg resp. a visit of the very scenic old city center of Bolzano/Bozen.(with the world famous Ice man Oetzi museum) or of Glurns, the smallest entirely walled city of the world.....
St. Moritz - Julier Pass - Thusis - San Bernardino Pass - Bellinzona isn't that scenic. I would do the whole thing the other way round:
St. Moritz - Maloja Pass - Chiavenna - Lake Mergozzo - Lake Como - Menaggio - Lake Lugano - Lugano (underestimated by Americans!) - Capoolago - Porto Ceresio - Ponte Tresa Lavena (all along lake Lugano) - Luino - Lake Magggiore - Laveno - car and passenger ferry - Intra - Stresa.
From Stresa, you could go on as planned (Simplon Pass - Forclaz Pass - Montets Pass - Chamonix) or reach Chamonix via the Bernese Oberland (with an intermediate overnight stop):
Stresa - all along Lake Maggiore - Ascona - Locarno - Bellinzona (famous castles) - Airolo - Gotthard Pass - Susten Pass - Grimsel Pass - Brig - Martigny.
Then either Martigny - Forclaz - Montets - Chamonix .... as planned, or
Martigny - Gd St-Bernard Pass - Aosta (charming medieval city center, Roman theater etc.) - Petit St-Bernard Pass - Albertville,
and then either Chamonix or Annecy.
Last day: back to Zurich by motorway (via Geneva - Lake Neuchatel - Lake Biel/Bienne)).

I love driving in the mountains, but you should never forget how tiring it is on narrow twisty roads where meeting trucks or even big camper vans in the opposite direction is often super stressful. It's the sort of area where you are happy to arrive at the next hotel already at 14:00 or 15:00 and be able to relax at last and have a drink.

If you read my previous thread, we have been doing these driving trips for over 25 years, and have driven many narrow, twisty roads where we encountered oncoming large truck and campers. We are both nature lovers, we prefer driving the scenery to the typical tourist sightseeing venues and we have thoughtfully planned this trip based on our goals and experiences. I would appreciate if replies would just focus on proving helpful information to help us tweak our planned route.

Oh well, then if you know everything already, you are wasting our time by asking questions.
Then again, if you think that driving over the Simplon Pass will take you to Chamonix, we do not have the same map. I have driven over it (loved it), but it took me to Domodossola in Italy, where I was happy to spend the night.

Day 5 is totally messed up. Alpe di Siusi would be after driving over Gardena pass, not "or". And Bolzano is in Italy, you cannot drive from there "into Italy." Too many passes that day and too long IMO.

(kerouac: On their map the Simplon pass drive will take them to Chaminox, not Chamonix ;-) )

I'm sure mikicook meant "into Switzerland". It sems to be just a missprint.
Idem for Chamonix.
Stresa - Simplon - Brig - Martigny (all highway) - Chamonix is perfectly feasible in less than a full day..

I’ve been driving in mainland Europe for about 40 years and have noticed that since Covid there’s more congestion on scenic routes, so you may find yourselves stuck in traffic more often than in the past. Also if you’re traveling on the first weekend of July the French roads are likely to be manic as residents from Paris and other main cities leave on their holidays.

I'm not sure these latest replies conform to the rules that the OP has set for us. They've made it clear they've been doing this kind of trip for over 25 years and have thoughtfully planned it all out. Hotels are booked and paid for, and the would like it if the replies would just focus on proving helpful information to help them tweak their planned route.

I would just ask that you take the advice given by P_M that you don't drive on the first day, however experienced you are, however many flights you have taken, micro-sleeps kill. They may not kill you but they might kill other road users and that is not the way to spend a holiday.

mikicooks writes:
"Day 1: arrive Zurich mid-afternoon, pick up rental car, STAYING IN Old Town Zurich"

That is what worried me, if it were "staying in old Zurich and pick up car in the morning" I'd be happier.

I was driving around Zurich and the airport in March and the number of idiots driving badly was pretty impressive.

thank you!

again, we are experienced at these types of trips, many have been overnight flights half way around the world with the airline package including rental cars picked up at our arrival airports. We appreciate the concern, but this consideration was the basis for our decision to only drive into Zurich for that first day and not attempt to go further. I AM ASKING AGAIN THAT RESPONSES REFRAIN FROM JUDGEMENT AND FOCUS ON HELPING US MAKE THE MOST OF THESE SCENIC ROUTES.

Thank you for the advice, but we are already aware of the increasingly heavy post-CoViD travel, as we travel frequently. If you reviewed our schedule, we are not near France in early July.