Planning trip to Switzerland in September or October

Is this trip for this year?

Yes, and I know it's going to be hard finding hotels, but we are willing to go a little later in September and October if necessary. We will be flying into Zurich and sleeping there the first and last night.

How many days in this beautiful country? For me, it's at least two weeks.
The BO should get the bulk of your time, 4-5 nights. No one is ever ready to leave, and it helps to plan for moody weather . You are going at a great time of year.
Zermatt is not my favorite, and it takes you further west. I would skip it, but many would heartily disagree. It also depends on how many nights you have.
I think the first week of October is the latest you should visit the Alps, as some of the lifts start shutting down by mid-October. There's an off season between the summer and ski demand, used for maintenance.
I would do Lucerne, the B0, and one other location if you have two weeks. You haven't mentioned fitting in the Bernina Express scenic train.
Hotels fill up quickly, so firm up an itinerary asap and book lodging.
You have a beautiful adventure in store!

Some good points to think about Pat! Is Appenzell worth it for culture?

Zermatt is not my favorite, and it takes you further west. I would skip it, but many would heartily disagree. It also depends on how many nights you have.

Interesting that you would say this. I'll be in Switzerland late August into September and currently plan to spend 3 nights in Zermatt, but the more I research the more I've wished I was spending that time in Murren instead. I have a week in Wengen afterward, but the whole BO area looks much more appealing to me than Zermatt. I'm pretty sure I could easily fill 10 nights in that area.

I'll be in Switzerland late August into September and currently plan
to spend 3 nights in Zermatt, but the more I research the more I've
wished I was spending that time in Murren instead.

I’m a huge Zermatt fan! I’ve been twice—once as a day trip and once for 3 nights—and hope to get back soon.

Adding links to my trip reports so you can see all the fabulous things I have done there.

https://community.ricksteves.com/travel-forum/trip-reports/solo-in-switzerland-june-2024-my-trip-report

https://community.ricksteves.com/travel-forum/trip-reports/solo-in-switzerland-my-trip-report

You don't have to spend a night in zurich at the beginning and end, as you can take train between the Zurich airport and Luzern in about 1.25 hours. So if you arrive in the morning, you might as well keep moving since you are unlikely to be able to check into a hotel early. Zurich is OK, but not as interesting as Luzern.

What do you think about making Spiez or Bern as a home base? Why do some people not like Bern, when Rick Steves says it's his favorite city in Switzerland?

Since you're spending all that money, and going all that way, capitalize on spending time and sleeping IN the Alps, not the cities. Bern is a lovely city, but it's a city, not in the mountains. I personally feel that Lucerne is the most charming Swiss city, and you still have access to Mt. Rigi, Stanserhorn, and Pilatus.

Bern is a nice, walkable city, with a very good tram system. Feels like a big city, and we like smaller towns better, but always do manage a day visit to eat at the Old Tram Depot, near the Bear Pit.

Don't know much about downtown Spiez, just pass through by train a lot. But for walking, it's a long downhill walk to the lake from the town.

Regarding Zurich hotels, I agree, you want to just fly in, and get a train to somewhere. For our last night, we normally have a morning departure from ZRH, and to checkin 3 hours before flight, we'd rather stay the last night at the Ibis Budget Airport in Glattbrugg. Very short tram to/from the ZRH terminal. 50 meters walk to tram stop. Small, clean rooms, good breakfast, pretty low price for Switzerland.

And the Swiss Rail Pass is so much easier than buying tickets everywhere. We love to take the boat all around Lake Lucerne. It's included with the pass, as is Mt. Rigi, and the boats on Lakes Thun and Brienz.

Ok so I'm thinking Lucerne would make a good place to take the train to after flying into Zurich? Do we buy our train passes before we leave home and we just hop on a train to Lucerne? What are some good hotels in Lucerne, we are now thinking around $300 a night now. Quiet and good beds.

Regarding Swiss Rail Passes, you can just buy them online in advance, or stand in a (long?) line at the ZRH airport. Once you have them, you're done buying tickets. Just hop on a train, tram, bus, or boat and show your ticket if asked, that's it.

BUT there are other options such as a half-fare card. And there are different durations you can buy, like 30 day, or 15 day... I forget all the options. This forum is full of threads about choosing which Swiss Rail Pass to buy, based on how many days and if the whole country is needed. You should search this forum for Swiss Rail Pass for lots more advice.

Does the Eurail global pass work in Switzerland, if we want to go to other countries?

Eurail global is valid in Switzerland, the (long) list of routes and companies,

https://www.interrail.com/content/dam/_new-structure/doc/res/sbb_validity_map_2026.pdf

note that those going high into the Berner Overland are only discounted not included travel (Lauterbrunnen–Wengen is on the included list). Watchfor recommendations for people using SwissPass which has greater coverage, notably bus routes, in Switzerland but none outside.

Thank you to everyone who responded to my questions, now I need to get busy booking airfare and hotels.