If you are prepared to skip Bellagio which I find commercialised, you could catch the train to Como & then No 10 bus or ferry to Argegno. From there a funicular ride up to Pigra, a walk up to Alpe Di Colonno, a pizza back in Pigra then back to Milan. Only complication is the lunch break for the funicular!
Weather permitting you will get great views of the lake & actually see some real locals enjoying themselves