Which way to go?

Well, that makes the choice a lot easier, because the road to the left wouldn't take us to the outskirts of Odysseus' territory, and when followed too far west it would also mean getting close to the city and plains, which wasn't part of his plan for now. It could only be the right hand turn and over the northern higher road.

Left or right?

...even then some evil spirit brought Odysseus to the outskirts of the land, to where to pig herder lived,

Odussey Book 24 line 138-141 Barry B Powell

Halfway up the road through the gorge there's a path to the North. Both road and path lead to the main road from Nidri to Vasiliki, but in Odysseus' days the connecting road wouldn't have existed. Even when Wilhelm Dörpfeld visited Lefkada a century ago, there weren't any roads connecting north to south on the island, the places were only connected by ship.

Right!

Fterno

But here we are at the junction, which way to go? Left or right?
A soul of one of the killed suitors says:

Unlike other European countries and other regions in Greece, Lefkada hasn't been affected by massive land redistributions, so the roads still follow the old tracks. They did modernise their mode of transport and trucks have replaced donkeys, who have all but disappeared from Lefkada, so the roads have widened, some have even been paved, though quite a few haven't. Apollonion hasn't changed much over the centuries, which is great for us, as we can still walk the paths Odysseus walked.

So, turn right is what we did and we embarked on the steep climb north up to the main road, after which we turned right again. Then we passed beneath Fterno, heading west.