There are two major gateways into Ticino: the St. Gotthard Pass in the northwest and San Bernardino Pass to the northeast. From the St. Gotthard Pass, the swift A2 expressway leads down the Valle Leventina to Bellinzona, where it joins with A13, which cuts south from the San Bernardino. A2 directs traffic flow southward past Lugano to Chiasso and the Italian border, where the expressway heads directly to Como and Milan.
As an alternative, there's the St. Gotthard Tunnel. If traffic is light, it can cut an hour off your travel time, but if the passes are closed and it's during the vacation period, tunnel traffic can be nasty. A car is a real asset here if you intend to see the mountain valleys but a hindrance in the congested lakeside resorts.