Once you have the tracking number, call Fedex. Explain to them that you're leaving town early and really want the package, so see if they will hold it for you at the local Fedex office instead of putting it on a truck. Then you can just go pick it up.
Alternately, since you explained that you're going out of town and you NEED the package, see if they can get the driver to make you one of the first stops.
Might work, might not. Worth a try.
Rob