Turns out, my little mare could definitely benefit from revisiting this early groundwork (early meaning fundamental, basic, terribly important).
Today was successful, minus one issue. She is acting like a bloodhound - when she is walking, she wants that nose buried in the ground. She will lift it when I say 'head up' but when I tell her to stop, she does but does not stand, she buries her nose back down and begins to walk away - nose to the ground.
Last week she started putting her head down the second I unclipped one cross tie, she's putting her nose to the ground when I go to bridle... I tell her head up, she listens, but I'm wondering if there are other ideas for when we're long lining and she does not stand still when we stop.