I don't think that Greece is in a position to launch offensives right now, especially as these would broaden the frontline considerably and into less defensive territory at that.
The first objective of any offensive should be to retake the Olympus line and retake as much of the Pindus mountain range as possible. More of Thessaly/Western Macedonia could be useful to access the area natural resources, especially lignite (how is mining going TTL
@Lascaris?) but strong defensive positions are key.
The place to launch a large offensive perhaps as early as 1942 in my opinion is Anatolia. Turks are essentially at the end of the line for reinforcements and once the Soviets join the war, they can be attacked from 3 sides. Which isn't to say that conquering and occupying Anatolia will be easy at all. It will mainly be a war of infantry, with a lot of guerilla formations on both sides, which could lead to unpleasantness ...