Let me share my experience:
I did similar years ago: scavenger run. The point of it was the same: no crafting, only looting.
The start was pretty easy, kited some crocs to the one skull fighters at the Noob river, looted their medium armor, than ran up to Sepermeru to have some decent-ish gear to proceed to the nordheimers and grab their hardened steel stuff and fur armor (vanir armor was good for surviving in the cold back then ).
Killed cimmeriands to have specter coating and star metal gear (THAT was mind blowingly loooong farm!), and armor, which was pretty quick.
Grabbed the Sword of the watcher, having plenty of mulled brew from Sepermeru chests, I visited the Kinscourge, murdered him, took a detour to the Frost temple to level up a bit more. And because I like that place.
Than I went to kill croc world bosses to have nice legendaries (not much, probably the Aja’s bane for undead with specter coating, and the Festering one to living stuff was the major ones). And the Mismourn to proceed to the next destination: VOLCANOOO.
If you enter there, you can have a free ice tea from the merchant (bug?), if you are like me, who avoided the jungle so far and not having any coins to buy tea. Slayed some dudes and serpentmen to get their gear - I found obsidian 2 handed swords more efficient, than other legendaries, because I could not find the one I wanted: Blade of the adventurer .
Then I just killed every major bosses. I would say it was waaaay different than playing the game casually, but was not that difficult. Only difficulties were the times when I died, and had to run back to my stuff (thanks cimmerians…). I was lucky (and skilled! heh heh) enough to not die in the frozen north AT ALL! I died in the volcano twice however, but Sepermeru had me mulled brews, iron picks, so running through the snow was not a hard thing to do while grabbing a handful of ice to reach my gear before I die from overheating.
Looking back from now I would say, swimming to east to collect gold to purchase a mercenary fighter (and let it kill one skull bosses in the ship to have the Seasalt cutlass) would have definately made my life easier at mid-range, but I wasn’t aware of that at that time. Plus another good advice: shields make your life easier against NPCs (but giving shields to slaves is still not a good advice).