I've seen a few searches land at this blog in the last couple of weeks looking for an elevation profile of the Great North Run (often with the search string "Great North Run Hills", or "Great North Run elevation"). So here it is:
The line shows the elevation (on the outer axis), the bars show the gradient (on the inner axis). So you get a nice downhill run at the start which doesn't feel so bad as it's along the motorway - as you near the end around km 18 and 19, there's what seems like a much steeper decline before you come into the final mile along the shore - the best bit of the race (once you get down the hill).
And, for good measure, here's a course map for the Great North Run:
Hope this is useful.