The tourist information office by the lake has free maps with the secondary roads clearly marked. Sometimes they run out, in which case you can try the tourist information office in Bardolino (there's a paved multi-use path along the lake from Garda to Bardolino which allows you to avoid the road & car traffic). The Bardonecchia tourist office is by the main lakeshore road: from the end of the path you have to go through the center of the old town inland towards the main road.

North of Garda the lake shore is hemmed in by Mt. Baldo, and there are tunnels towards the northern extremity (north of Malcesine). The lakeshore road on the northern half of the western shore also has lots of tunnels.

If you go during the warm-weather months, there can be a lot of car traffic on the lakeshore road, which can be very intimidating.