I don't think there was a specific territorial divide between Dol Guldur and Mirkwood. At least we know there weren't any signs saying, "Welcome to Dol Guldur: Prepare to undergo everlasting torment for the rest of your pathetic life." [img]smilies/biggrin.gif[/img] I think that the "border" of the land stretched as far as the Orcs or other evil creatures were willing to go, to harry travelers in that area, and perhaps even raid the Elves. I think Dol Guldur's main function was to act as a distraction and an annoyance for the Free Peoples, so that their full attention would not be fixed upon Sauron. Khamul would probably send forces out now and then, perhaps in league with Isengard, to perform specific "functions" or "missions."
About the surprise of the Elves, I don't think they were expecting an all-out attack. All they were prepared to deal with was Gollum's little hissy fits and arguments. The reason that the Orcs' ambush succeeded was that the Elven guards probably became used to the routine of "let random slimy Hobbit-creature up into the tree, let random slimy Hobbit-creature come down the tree, take random slimy Hobbit-creature back to the dungeon, and repeat." They were probably only lightly armed, and were definitely taken unawares by the (relatively) large number of Orcs in the ambush. I'm sure that once the fighting started, other Elves "sensed" the Orcs' presence, and supplied reinforcements to those guards. But, of course, it was too late, and Gollum had escaped.
__________________
But Melkor also was there, and he came to the house of Fëanor, and there he slew Finwë King of the Noldor before his doors, and spilled the first blood in the Blessed Realm; for Finwë alone had not fled from the horror of the Dark.
|