Seems like a nightmare getting from interlaken to Italy

Bellagio is hard to get to no matter where you start from. Have a look at a map, and you will see.

Basically your options are:
- Wengen to Como, then either bus, boat or taxi.
- Wengen to Lugano, bus to Menaggion, then boat.

Te train part you can find on www.sbb.ch. For busses in Italy google maps is often good.

Youi can also make your life easier by going to Como in stead of Bellagio. Or you can make it interesting by going to Varenna, and going there via the Bernina Railway...

I like Wengen's suggestion to go by Bernina to Varenna. Stunning! Then a ferry across the lake to Bellagio. That, to me, sounds like a very nice day. We did similar. We took the Bernina from Chur to Tirano. Switched trains which is literally getting off the Bernina turning around and walking 50 feet to the train to Varenna Esino. Then walk downhill to the ferry.

One person’s “nightmare” is another person’s adventure.

Forget flying; you would spend more time and energy getting to and from the nearest practical airports (Zurich and Milan), and allowing for security etc., than the train trip.

There are 3-4 possible routes for you, using a combination of trains, boats, and bus. WengenK gave you 2 options, both starting with Wengen—-Lauterbrunnen—-Luzern, then train, boat or bus on your way to Bellagio. They also mentioned suggested, and Jules endorsed, the Bernina Express, which would take you by train for all but the last leg, the ferry from Varenna to Bellagio.

The route via Spiez and Milan has not been mentioned due to a track closure on that route, with a bus substitute. That is in effect June9-Sept.8, and if your trip is later than that you could consider this route as well; it is often faster and simpler, particularly if you can take the direct train from Spiez to Milan.

Whatever you choose, you could make it more pleasant by breaking the journey with an overnight stop somewhere nice along the way.