Not quite Peter. When you receive an IFR clearance in the US it will be the route to, and including, your destination - even if that's the other side of the country. It may be abbreviated with the statement 'as filed' as part of the route. If the clearance will be a major modification of the filed route then they'll forewarn you with the statement 'full route clearance'. A clearance with vectors will include a point on the route where the vectors stop and normal navigation starts.
ATC may subsequently modify things in flight, but unless that happens you have a clearance all the way to your destination. Even a modification will get you to your destination, either via a whole new route, or the modification joins the old route.
Last edited by Tinstaafl; 3rd Jul 2012 at 17:14.