Rank and Cone.
One thing about this is that occasionally I have had a ground unit group simply stop when I had it changing formation between off-road, rank and cone. I seem to recall it was dependent on the number of units in the group.
During your mission creation, you might want to do a mission run through (at accelerated speed) watching your ground units to double check they do change formations correctly and actually travel all the way to where you want.
While I'm talking about the ME and ground units - don't forget they can't cross rivers unless you have them on-road and using bridges. Also, if a vehicle is off-road and in hilly terrain, it can only handle a gentle slope, it won't go up or down any kind of vaguely steep hill.