The Original Plan for the Fellowship?

[Belegorn]

Originally Posted by Inziladun

Well, Sauron was in a sort of powered-down state then, and I don't think security was a very high priority in Dol Guldur.

I think it was still a grievous place to try to not only infiltrate but to escape from. When Boromir spoke of how entering Moria would be like walking up to the gates of Mordor, Gandalf told him that is was hard to enter and then leave Sauron's domains, but he would not lead them into Moria if there was no way out.

Originally Posted by FotR, bk. 2, ch. 4, p. 354

I alone of you have ever been in the dungeons of the Dark Lord, and only in his older and lesser dwelling in Dol Guldur. Those who pass the gates of Barad-dûr do not return.

Gandalf was saying it was not like entering one of Sauron's strongholds, even his lesser one, if they were to go under the mountain through Moria.