Some more options for game types that fits under the broad umbrella of my Border Brigand creation.
1. If you have a third player with a big army, you could make the Brigands a substantial force, the size of either army, or only a few hundred points cheaper. The objective would be for the Brigands to hold out, while the attacker and defender are trying to capture as it was set up originally. in this case the defender would not have to wait two turns before showing up. This is another case where the best player/army gets the middle to prove how good they are. Same victory conditions as the original version
2. You could make this a relief force game. Where it is the defenders units holding the Watchtower and camp, and this separated force has to hold out for reinforcements. What used to be the brigand force could be up to 40% of the defending forces whole point total. In this game make the rest of the defending army arrive on turn two. I think this is already a game type, i just add in required terrain features. same victory conditions as the original version.