Regional train

Its a regional all 2nd cl train. You can buy at the ticket counter or from a vending machine.

Regional train tickets are valid for 60 days from the date of purchase, so you can easily buy these tickets at any train station in Italy.

Don't forget to validate (date/time stamp) your Regional train tickets prior to boarding the train.

You can check train schedules on the trenitalia website.
Make sure you sit on the left side of the train when you leave Milano Centrale for better views of the lake.

It takes 1 hr 3 minutes to travel from Milano to Varenna.

Once you arrive in Varenna, you may want to walk or take a taxi to your hotel.

The taxis line up behind the train station & they will charge you €10 to drive you to your hotel.

This is the website for the ferry schedules: http://www.navlaghi.it/eng/c_illago.html

Have a great trip!

Sorry, I may have deleted a copy of this question that had some answers. However, you're covered with the info on this page.

The best way to purchase them is at the Milan train station, whether from a ticket machine, staffed ticket window, or the travel agency inside the station. Buy your return tickets at the same time, since the station in Varenna doesn't sell tickets (although he travel agency in town does). Regional tickets do not specify a date and time, only a route and class of service. Before boarding the train, validate the ticket/s for that day's direction of travel, which stamps on a dated and time.

Just to continue a bit. Buying Regionale train ticket on line is NOT recommended since the on-line ticket comes pre-validated with a four hour window to use. The only exception if the Regionale ticket cames with a single ticket on multi-legs. In other words, if going from A to D is a single ticket with changes at B and C. Assuming the train between B & C is regional then that regional ticket will be included with the total ticket from A to D and purchasing on-line is fine.