Are all Swiss trains and boats bookable on SBB?

Yes, all can be booked on SBB app, website, desk at train station or machines at train station. Just make sure to chose half fare card at checkout for any of those options to get the correct price and always have your HFC QR code handy on the train when they come through to check tickets.

Far as I know, there is no "booking" on the boats or chairlifts. I'll get corrected if that's wrong. For trains, at least in spring and fall, there's no reason to pay for First Class, or book seats. We get Swiss Travel Passes, and we simply walk onto the train or boat whenever we feel like it. On the train we get on a 2nd class car, on a boat, we do not enter the First Class Lounge area. It's not at all like the airlines (it's much better).

For the Panorama Express, same thing. In spring or fall, we just get on a 2nd class car. They always seem to take the same route as the Panorama Express car they are attached to, and have nice big clean windows. Others will know about what that's like during big tourist season.

As mentioned above you are not “booking” anything, just purchase a ticket for the journey and get on.

Pilatus is now suggesting that people reserve a timeslot for the cogwheel train portion of the trip on sunny days, weekends, etc. You will see this information as a banner on their website:

https://www.pilatus.ch/en/

I have used the SBB app for many years now, but have never purchased a Golden Roundtrip ticket on there. I would be curious to know how this is done.

Here is where you can buy it on their website, and reserve the cogwheel portion as well:

https://shop.e-guma.ch/pilatus-bahnen/en/tickets/c/golden-roundtrip-1075471

The Golden Round Trip is a special package, not just a public transport ticket, and that you will have to obtain at the ticket office in Luzern. Should not be an issue. You can reserve your slot for the Pilatus railways at the same time.

The Golden Round Trip is a special package, not just a public transport ticket, and that you will have to obtain at the ticket office in Luzern.

This is what I thought, thanks for the confirmation. Perhaps Wanderweg missed the fact that they were asking if this specific package could be bought on the SBB app when they affirmed that all tickets could be purchased that way.

Thank you all for the replies

Yes, I was specifically wondering if the Golden round-trip could be booked through SBB app, and it appears the answer to that is no.

I will try to book that through the link you provided, looks easy enough— and since we are only in Lucerne for one full day, I already know that is the day we are going whether rainy or not!