Well if by success you have ask oneself how far East does the German Army need to get to, does the German Army stop at the River Volga, Ural Mountains or push on past into the East Ural Industrial region, could the Germans do this.

Astrakhan to Arkhangelsk line following mostly the River Volga was entirely achievable for the Germans by winter 1942.

The Ural Mountains down to the Aral Sea was plausible.

But anything beyond that stretches the supply lines to snapping point, but to achieve total victory the Germans would have to commit to going beyond the Urals and this has one major problem and that troop dilution. But even this could be overcome if Hitler had decided to get all minority groups to come to his and Germany's side act as a liberator to fight the common enemy Joseph Stalin.