I remember a friend told me about his climb up Kilimanjaro. He prepared the entire year for that. On his way up, he saw bodies just frozen in time. He didn't get all the way to the top and had to go back down with his guide. His guide told him afterwards, that many people believe themselves fit enough to climb tall mountains, but end up dying along the way due to the thinning air.

Moral of that story is: people venture into the unknown believing they are 'fit' enough to do so, but end up dying along the way. So in your case, prepare, prepare, prepare.

I've clocked 350 hours in the game. Died a few times on the mountain. Never had problems retrieving my loot. Then again, not only did I prepare for multiple deaths with a castle full of gear, but I had built up a fortified location at the base of the mountain with a portal.