The problem is, as far as we know their southern settlement that was closest to us was only their summer retreat. I'm not entirely sure all of our warriors can continue to prosecute the war while the Northlanders move north to their other encampment, and thus keep up the pressure. Our Frost Scarred can only do so much.
I don't doubt that if we find their herds we can force them to capitulate the problem is locating them in the first place, which I'm not sure what action helps the most with that.
Thats mostly due to thinking in terms of modern/medieval war.
In this conflict, remember the following elements:
-Our warriors are professionals, theirs are hunters. Thus, we can commit to a fight for far longer than they can afford to, and we can maintain this mobilization indefinitely. They cannot, every single hunter used in the fighting is costing them food production and
they do not have food preservation. Their only source of food preservation is meat on the hoof.
-Their summer camp is actually essential. Its where they go to have children and generally expand their population. If they lose it, it's going to be very hard on them to lose their richer camp, so if they lack cultural values forcing them to keep fighting, they are likely to grudgingly capitulate at this point.
-The herds are actually only semi-domesticated, and follow predictable migratory routes. We have dogs chosen for intelligence, we can track these routes, though cornering them would be difficult, harassing them is possible.
-Their cavalry is not widespread. You can ride caribou, but only the very largest beasts(usually the top stag) are ridable by adult men, though its also likely that the Northerners are genetically disposed to smaller sizes due to the colder climate.
Basically, don't expect easy victory, but they CAN be squeezed to death.
Would it be the travel action we use then for this? As I don't think we have a herd action or anything.
Study Travel basically generates Travel related innovations, shaped by the present needs(how to chase highly mobile raiders) and inspirations(those people being on animal backs).
We can potentially get there with Hunt(Orkers) or Hunt(Prize Animals), but Hunting primarily makes food rather than innovations, so the chances are lower...also we need that megaproject because our area's Hunting is going to be wiped out soon by us, and the largest creatures other than our pet orkers already HAD been hunted out according to the previous turn.
Not that a second temple would be bad as an option. We do want a temple to 'cap' our Crystal Lake wonder. Its just expensive in food and manpower at a pinch time
What exactly are you hoping for? For us to develop the concept of cav now and somehow hold on to it long enough to get Orkers to a ridable state? Because that seems like a long shot.
Orker rodeo fits our values.