Suppose we had a mix of A and B. Send a small force to delay Rudolph with guerilla tactics, or, even better, just dig in and defend the opposite banks at the River March, and at the same time send the bulk of our forces to swipe Vienna. Of course the delaying tactic could possibly be suicide...but the troops need not know that.

Final Answer: I say send a small group of men to fortify the bank opposite of Rudolph at the River March, dig in and commit to defense, while sending the bulk of our knights and army straight to the lightly defended Vienna. We'll take the rug out from beneath their feet all at once. And if we take Vienna quickly enough, possibly send notice to the delaying force to make a hasty retreat.