PaunchyPirate
Thinks s/he gets paid by the post
Your itinerary looks good to me. Personally, I think you might want to plan some half-day or daytrip activities out of Luzern. The City itself is quite small and you can cover most of it in a day or less on foot. Once you have seen the ancient bridge and the downtown area and admired the fantastic mountain views across Lake Lucerne, you have covered most of it. Unless you want to take in the National Transportation Museum (which is nice, but unless you are a transportation nerd, there are better things to spend your time on). Day trips to Stanserhorn, Mt Pilatus, Engelberg (Mt Titlis), etc are amazing. For something unusual, consider taking a quick train or a slower boat to the Luzern suburb Hergiswil and visit/tour the pretty famous glassblowing shop "Glasi Hergiswil". Interesting museum, live glassblowing tours, shop.
You have a lot of amazing train rides planned - I wish you a fog-free, sunny and crisp Autumn! If the weather cooperates, you are in for a treat!
You may want to plan some alternative activities in case of bad weather. For example, in the Interlaken area, Swiss Open Air museum at Balenberg is really nice. Traditional buildings from all parts of Switzerland, trade and crafts demos, etc. Of course, lots of indoor things to do in the cities. Museums (Landesmuseum right next to the main railway station in Zurich, or visit some castle like Kyburg (outside of Zurich) or, as some other poster already mentioned Chillion Castle outside of Lausanne. There are many more, of course and all are readily reachable by public transport.
Thanks for the feedback. I probably should added that the specific activities for each stop on my itinerary aren’t fully nailed down. But, I definitely plan on getting outside the central areas in places like Luzerne. If there’s a funicular or cable car in the vicinity, you can bet I’m going to try and ride it. I’ll go to the top of anything for a good view! I’ll work on that next level of detail next after I pin down a decent plan for where to stay and for what duration.