graph targetting

no one bothered to respond before so it looks like im making yet another page for this

i created a vehicle and a grid ( graph)

my vehicle originally needs to have a game object in order for it to go after the target. Now it needs to be able to find a spot hidden within the graph that the player chooses and go after it. these targets are not gameobjects and i guess i should also tell you they are clones with one named its master.

all i need is a way to target the object without telling the vehicle. its needs to be able to search for it on its own. any ideas?