[Galadriel55]

Regarding the escort, perhaps Boromir's pride would not allow him to accept one, even if Denethor wanted him to have one. This isn't your usual trip up the mountains; it's a quest with something mystical to it. He may have said that he will go seek Rivendell with the same attitude as people said that they will go seek the Holy Grail. He would also want to prove himself as a hardened warrior not just in battle, to show that he is able to survive and accomplish his mission without an escort.