HA we just wrote opposite things!
Here's the thing though with that theory...why would HG be seen leaving Tempo with JM , likely in a car, but then be walking on foot through the projects. That's still a good distance from the DM when your on foot. If she could hardly stand would she really walk that far? And if JM was after her, would he really let her?
The other thing is a think its far more likely she was coming from the point, trying to get to the DM, I think she thought she could take a cut through, but then realized it wasn't the greatest place to be cutting through, its really confusing in there. So she gets herself to a main road, and sees Mcgrady's as a reference point. Because from that point on she heads straight to the DM.
Additionally I'm in disagreement with you on that being a likely route for JM to dip out f town. He would have just followed water up a few blocks turn left onto ridge...which is a straight shot and becomes OLR. Its also almost immediately becomes a residential area, then farm land.