Basically someome needs to create a website that looks up the route of the package and then queries the nearest runners asking if they can full fill the order for X amount of btc(along with estimated amount of $$$).
Sounds simple
What if runners are unavailable to pick up packages like they promised? (family member died, rush to hospital , some other extreme reason?)
Possibly depending on the package they could post it to the next runner. At least message someone about it and the site could notify another runner in the area if there is one.
The important part here is "communication".
The gps device would be nice too. Especially for dead drops