Oh boy. What to do in Switzerland?

What time of year? If your schedule allows, go for 4 nights, at least.

Stopover in Bern, but focus your time in the Bernese-Oberland (Interlaken is 1 hour from Bern). Visit Murren, Lauterbrunnen Valley, and Jungfrau. A day trip to Lucerne and Mt. Pilatus should be on your radar, but the schedule might be too tight to squeeze in a day trip.

If your schedule allows, spend a day and night in Zermatt and visit the Matterhorn as you make your way down to Milano.

Thank you, Bradley!! I think you're right; Lucerne has been on the radar, but is possibly too much for this itinerary.

Would you sign off on this itinerary:

Basel to Bern (overnight in Bern)
Bern to Interlaken (1-2 nights in Interlaken)
Interlaken to Montreux (1 night)
Montreux to Zermatt (1 night)
Zermatt onto Milano.

May ditch Montreux if I can't swing it; I'm on my way to the Italian Riviera so I wouldn't be completely heartsick if I missed this, though I do want to see it!

I don't mind a little extra train time, because I have work to get done anyway, and would just as happily do it on a train as in a hotel room. One of the downfalls of working abroad, I suppose.

If you have three nights, spend them all in the Berner Oberland. I recommend Murren - it's spectacular. Even with four nights, I'd probably spend all the time there. That way if you get some bad weather, you have more time to wait it out. If you don't want to spend all your time in one place, spend a night in Lucern. It's worth two nights for sure, but I would not at the expense of the Berner Oberland where you really should stay at least three nights. Bern is also nice, though not as scenic as Lucern. Lake Geneva is also beautiful - I recommend Vevey or Lausanne. I would not go to Zermatt for only one night -- it's just not enough time and the weather is very iffy there. You might not even see the Matterhorn.

Interesting news about Zermatt. This is so impossible; I want to go everywhere! Sounds like the Interlaken region is a lock, though. Will definitely overnight in Bern and onto Interlaken first thing in the morning.

Maybe ditch Bern and do this:

Basel to Lucerne for the night (I'd get to Lucerne by noon and have time to check out the town)
Two nights in Interlaken
One night in Lausanne (I know that's not spelled right)
Then onto Milan. Maybe I'll just see the Matterhorn from the train! (It's my white whale).

Sorry, erin, have I missed what time of year this trip will be?

also, what do you mean by white whale?

Nigel--think Moby Dick.

October 2016! Also, sounds like if I'm going to Interlaken, I might not want to stay in Interlaken property, but instead make my way to some other little village in the region. Thoughts on which one?

If you've been to Interlaken already, then yes. try Murren, seems to captivate most folks, otherwise Lauterbrunnen if you don't mind staying at valley level rather than higher up. Not sure here, but I doubt you'll see the Matterhorn from any train other than the Gornergrat. Save that for another time, there are more than enough mountains in the Berner Oberland to enjoy, trust me.

I'd cut out Lausanne personally, just do Luzern for a night, then train to Interlaken via Brunig pass (gorgeous scenery), and take the train/cable car to Murren. Stay for the other 3 or so nights there, then take the train from Interlaken to Spiez, and change to the Lotschberger line south to Brig. This is slower than the usual route that goes through a long base tunnel, but it's another scenic route - along old viaducts, and looping back and forth through 2 horseshoe turns to gain altitude. From Brig, take a train via Domodossola to Milan.

I think I'm sold on Murran. Question: is there a reason to choose Murren over Grundelwald? Only because that looks equally quaint but nobody is suggesting it, and I wondered why. Thank you all so much for all your help! This is phenomenal!

O my stars - do NOT stop in Interlaken. It's just a transportation hub with trinket shops and McDonalds and some fancy butt hotels and restaurants. Where you want to be is BEYOND Interlaken Ost about 20 minutes by train brings you into the Lauterbrunnen Valley with Murren on one side of the alp and Wengen on the other. These are the villages and destinations where you want to go to see the splendor of the Swiss Alps. Leave Interlaken behind.

Poor Interlaken. As I've said on another thread, it's a nice town and a good introduction to the BO, but compares unfavorably to villages further in.

Grindelwald is OK and has many attractions nearby, but it's a valley town and so doesn't have the same high altitude, car free feel as places such as Murren and Wengen. Rick Steves in particular doesn't like it as it's too touristy and doesn't fit in to his "Back Door" philosophy.
Worth a visit though.

It might be good to get the names right. Spelling counts, I'm afraid, when there are completely different places with absolutely opposite vibe but similar names.

There is no Grundelwald.

There is Grindelwald, as mentioned directly above, which is a low altitude ski resort type town with cars, lorries, buses and trains in a completely different valley from the Lauterbrunnen Valley. The trains from Interlaken Ost turn left to reach it. Many big hotels and lodges.

There is Gimmelwald, a tiny outpost of a hamlet on the edge of the cliff below Mürren and above Steckelberg at the very end of the Lauterbrunnen Valley, reached by cable car from the valley, reached by cable car or walking from Mürren. No vehicles except very small specialised farm equipment, everybody on their own two legs. Maybe an occasional bicycle. Fairly basic lodging including in a loft on straw. OK pizza but with a killer view.

Chalk and cheese.

It is good to know which you mean.

No, there's nothing wrong with Interlaken. It's not a bad place. It's just that 20 minutes more on the train past Interlaken Ost will take you to a world like you've never seen before (Lauterbrunnen and the surrounding Alpine Villages). "Interlaken" has just been thrown around in travel circles so much that that the name is synonymous with the Swiss Alps. But Interlaken is "almost" in the Swiss Alps. 20 minutes apart but a world of difference!

Ye I agree with what you say Tim, but when you come from a place as gently undulating as the UK, Interlaken, with the mountains in the distance and the foothills on your doorstep, not to mention the lovely turquoise colour of the river water, really is a world like none you've seen before! But by all means skip it though if time is short!