Some people basing themselves for Monza want the fastest possible commute. Others want a place worth waking up in even on the days they're not at the circuit. Lake Como is for the second group, and it's worth being honest about the trade-off before recommending it: this is not a quick hop to the track.
Varenna is the practical base of the two main options. It has its own train station with a direct Trenord service to Milano Centrale in about 64 minutes, running roughly hourly from 05:35 to 21:35. From there, getting to Monza means either continuing on to Milano Centrale and picking up the separate direct Como–Monza line, or routing via Milan generally, since there's no single direct train from Varenna to Monza itself. Realistically, budget close to two hours door to door on a race day, not the "quick weekend trip" some guides imply.
Bellagio, the more famous of the two towns, doesn't have a train station at all. Getting there means a ferry from Varenna (about 15 minutes, running hourly, first departure 6:45am) or a bus from Como (just over an hour). It's the prettier base of the two, with genuine promenade views and a slower pace, but every day you head to the circuit adds a ferry or bus leg on top of the train.
For where to stay, Varenna keeps things simpler. Hotel Olivedo sits two minutes from the ferry pier in a Liberty-style 1896 building, though it only operates February through October, so check dates if you're eyeing shoulder-season travel. See live rating and reviews on Google Maps. Albergo Milano, a few hundred metres away, runs a strong reputation for the price. See live rating and reviews on Google Maps. In Bellagio, Hotel Belvedere has been run by the same family for five generations and looks straight across the lake and up toward the Alps, which is the actual reason to choose Bellagio over Varenna in the first place. See live rating and reviews on Google Maps.
The honest recommendation: this works well for a longer stay where race day is one part of a bigger trip, less well if you're trying to squeeze in three tight circuit days around a day job's worth of commuting.
