...I just want him to go to the closest one and stay there until it's down then find the next closest one that is marked...
That would have been good to know when giving advice on your previous comments. I figured you still wanted it to be point and click so gave advice on that.
Either way, I would make the minion into a state-machine. Something like idle->find->move->arrived->chopped->idle. You would have an instance variable for "state".
if state=idle then set state to find and find path to closest tree
on path found set state to move and move along path.
on arrived set state to chopping and set timer
on timer destroy tree, add to wood variable, and set state to idle
(thus, since idle again would find closest tree and start the cycle over again)
So with those events I left out arrived but depends on circumstances of what you need. Shouldn't really be too hard if you understand state-machines and can get that cycle down