This is pure conjecture of course, but Gary Grigsby's old Western Front game, which would be the progenitor to WITW much as War in Russia precedes WITE, had the following scenarios:
1. Diadem - starts on May 17, 1944 and is limited to the Italian Peninsula as far south as the Anzio / Monte Cassino / Hitler Line area, and as far north as Milan. The Allies need four out of: Milan, Venice, Bologna, Florence, Livorno and Genoa. Runs until Oct 1, 1944.
2. Overlord - starts on May 17, 1944 and covers the entire Western Front. As far North-West as Leeds in Britain, as far North-East as Poznan/Rostock, as far South-East as the Italian Peninsula covered in Diadem and as far South-West as Bayonne in Southern France. The Allies need four out of: Berlin, Hamburg, Essen, Cologne, Nurnberg and Munich. Runs until Jul 1, 1945. The start date was deliberately set earlier than Jun 6, 1944 so that the Allied player isn't limited to landing in Normandy all the time.
3. Breakout - starts on Jul 24, 1944 and covers Southern England, half of France as far South as Nantes / Dijon / Tours, the Low Countries, and parts of Germany as far east as Stuttgart, although victory conditions only extend as far as the Allies requiring four out of: Essen, Arnhem, Antwerp, Aachen, Cologne and Metz. Runs until Nov 1, 1944.
4. Bulge - starts on Dec 16, 1944 and covers much the same area as Breakout, minus parts of France/Britain farther East than Le Havre / Dover. The Allies need five out of: Antwerp, Namur, Bastogne, Liege, St Vith and Luxembourg. Runs until Feb 1, 1945.
Refresh my memory, but is WITW supposed to cover the period 1939-1941, such as the invasion of Norway and the Battle of France? I'm guessing yes, and then nothing more Southern than Sicily, since they're also planning War in North Africa. That would seem to leave out the Balkans/Crete though, unless North Africa also covers that.