A possible idea is to try and draw the units off the mountains, keep a space between the mountain and fortify the units. let them charge in and we'll win. then my idea is to move the whole force ontop of lookout mountain, depending on the size of the force we then fortify there for awhile heal up etc, if its small leave the units their and spend the whole GA building up military units moving them down there and by the time the GA has ended we can then move on the first city.
An alternative would be to get the whole stack and circle around the outside of the viewpoint of the mountain, this would however be fairly dangerous as it would leave us unprotected.
one thing i am curious about though is why during out golden age are we spending that time building horsemen, warriors and curraghs? imo the curraghs can wait until its finished, warriors are simply ppintless unless as a scouting unit if that is the case we can just wait until the GA has finished and why are we building horsemen when we can build immortals? the extra movement point is not better than the 2 extra attacking and 1 defending bonus we would gain.