Why Did Isildur Cross the River?

[Inziladun]

Originally Posted by Sarumian

Could Isildur have been confused by the Ring? If it had started it's famous love-hate game with him, he could have wished both give it away and keep it at the same time. Elrond was with Isildur at the Cracks of Doom and tried to persuade him to destroy the Ring. Isildur could have thought that unlike to himself, Elrond was able to have it done and he needed to bring the Ring to Rivendel, but secretly. At the same time Rivendel was far away and the Ring could have influenced Isildur to take this long way as he didn't need to give it away too soon. He could also have been reluctant to bring it neither to Lorien, nor to Kazad-Dum, as there was a risk that someone else clamed it there.

Interesting. So the Ring wanted to forestall its being given away by Isildur?
The problem I see with that is that when Isildur set out from Osgiliath, it was still his intention to take the Ring all the way to Arnor with him, to have it be an 'heirloom of the North Kingdom'. It wasn't until the attack by the Orcs near Mirkwood that Isildur realised he lacked the strength of will to use it, and declared it should go to the keepers of the Three. Even then, I doubt very much he could have actually parted with the Ring if it came to it.
I guess Ibrin's thought that the Ring pushed Isildur to his route because of some connexion with those Orcs looks the most probable, but still...why were the Orcs on that side of the River anyway? They originally were assigned to harass any forces of the West attempting to cross the Mountains, a task at which they failed miserably, since they ran from Gil-Galad's Elves and the Men of Arnor marching to the War.
After Sauron's fall, they had been too cowardly to attack Thranduil's forces returning to Mirkwood. Why then did they not return to watching the Mountain passes? Surely I don't have to put this down to 'another Ring-event which happened because it was meant to'?