Some additional details that I should have clarified before. ;)
The clans don't exactly know where the Inner Sphere plans to defend, but it will be in the general area that the canonical battles for twycross tend to take place. This means the plain of curtains, the great gash, and the area around the capital city of Camora.
Based on my readings, the Plain of Curtains is generally a favored landing site since it's big enough and flat enough to land and organize a large force. The final goal of any campaign is general Camora, since all the important stuff is there. Between them is the famous Great Gash, which, as I understand it, is a long, twisty, high walled, but narrow pass that can effectively be blocked with explosives. Beyond the Gash, the area around Camora tends to be quite rugged and tough, with a number of additional small chokepoints around the city (three of these chokepoints feature in the Twycross scenario pack of old, where a company of defenders tries to hold each one against attacking clan forces).
The weather will be calm to atrocious, generally at random. This may mean air operations in certain areas will suddenly become impossible. This doesn't count the Diabolis storm, which will be roaming around the plain of curtains and will remain just atrocious.
Whichever force wins the bid, I will employ them in the manner that I believe will most likely bring a clan victory without undue dishonor. Unless there is a specific plan specified by the bidder, in which case I'll do my best to execute that plan.
At present, the bidding remains open until saturday night. Any continuances will depend on my health. :D