Milan to Lake Garda area

For lake Garda I recommend a car, as it is very big (long) and the train stops only in the south (Desenzano or Peschiera).
I like the north lake, which however has no trains (only buses).
If I were to stay in the North (my preference) but without a car, I would choose Riva or Malcesine. Both can be reached by bus from Verona.
If you want to stay in the south, where the rail line Milan-Verona-Padua-Venice passes, then Peschiera or Desenzano are the only choices.

Jo,

I visited Lago di Garda last fall, and the "best town to use as a home base" will depend to some extent on whether you want to mostly stay close to that town, or explore the area more.

As Roberto mentioned only Peschiera and Desenzano have rail stations, while the towns at the north end are only accessible by Bus, boat or rental car. I stayed in Peschiera and that would be my suggestion for a "home base" for the following reasons......

• it has good rail access so you can easily get to nearby towns such as Verona for day trips.
• it also offers access via bus to attractions like Gardaland (if you like amusement parks).
• it's a smaller town with a nice character and it's easily walkable in most cases.
• there are some nice hotels there.
• in addition to rail access, it also has convenient access to the boats, so you can easily take day trips to any of the towns along the lake. Peschiera seems to be the "home base" for the boats, as that's where they dock at night. In order to minimize travel times on the lake, use the fast Aliscafo or Catamarans if possible.

In terms of "ease of transportation", Sirmione would be the worst choice for a "home base".