I'm playing stock Valheim and no cheats. I guess there really isn't a good way to get large amounts of ore down a mountain? I currently have a small shack up on the mountain with chests and a portal by it. The portal lets me go to my main camp to repair equipment, sleep, food, etc. The chests store the ore. I move the shack around as needed based on silver vein deposits.
I've been getting my silver in piles of 30 and loading up my dude. I then do a controlled descent down the mountain until I run out of stamina (I usually do this with at least 120 units). I then toss some of the ore ahead of me until I regain stamina. Rinse and repeat. I finally manage to get to my cart, and then go to my boat parked off in the distance (and then loading the boat is kind of annoying too)
I've done this now about 5-6 times and am close to being all the way upgraded with silver age stuff. I would not be opposed if the developers had a way to teleport the silver somehow – maybe not the ore, but if it was converted to bars? IDK. Just trying to think of a less tedious way.
The guy that posted the "stairway to heaven" video today (crap ton of ladders to get up the mountain) inspired my post. I watched some other folks ride carts down the mountain – honestly have not tried this but don't think it would end well.