Great idea this poll, rich. About my vote, although I would love ALL middle earth covered by this wonderful game, I think that a great place to visit after Gondor could be the lost realm of Cardolan (your B option).
And I say so thinking in the multiple options we can get in these lands. For example, I would think something as the following:
1- Bandits arount the Gwathló.
Our fellowship could get to Minhiriath (the southern part of Cardolan) by sea with a message to Bree, and on arriving there, they are warned about lots of dunlendings bandits from Dunland and Enedwaith, plaguing the remnants of Cardolani people that live around the mouths of the Gwathló. Here we can get some new foes as the Dunlendings.
2- Ruins of Tharbad
Going up the river in a boat, they finally reach the ruins of Tharbad, and in this journey they can get some nasty river treacheries and locations in tharbad.
3- Spies within Bree
Finally reaching Bree, we can have here some hobbit interaction, and some quest of helping the Rangers uncovering dark spies within the city (maybe Saruman's agents that can lead lately to Isengard).
4- The Barrow Downs
The pursuit of Saruman's agents lead our heros to the Old Forest, and lately to the Barrow Downs, where we have the undead as new foes.
5- Retreat to Amon Sûl
Having to fight their way out of the Barrow Downs, our heros retreat to Weathertop, having to fight back the hordes of undead.
6- The Gap of Rohan
Free of the undead, our heros address south following the lead of the agents found in Bree. Here they could meet the Half-orcs of the White Hand along with the Dunlendings again due to travel across their lands.
And this could lead to a new cycle in Rohan.
What do you think?