Will my FedEx package due tomorrow and is 140 miles away really come tomorrow?

It absolutely could arrive on time, because the LAST time it was scanned probably was either in transit, or "received at fedex location" meaning it is out for delivery, or (in your 140 mile case) will be out for delivery tomorrow. Between the 140 miles and tomorrow, it is going from the fedex distribution center, to your local fedex delivery office.