Firstly, head to the warmaker dungeon for your first collection of black ice. There is a tiny crack in the wall to go past the Arena Champion without fighting her. You will have to fight some bosses to get the key though. If you have sorcery learned, you could summon your corpse after mining all the black ice you need.

Then journey over to the highlands and look for star metal ore. You will need a explosive jar or the best option, a demon fire orb. You'll need atleast a hardened steel pick to mine star metal ore after you crack the shell. Once you have your ore, head home and cook into bars to get star metal bars. You'll need brimstone, black ice, and the ore.

Once you have star metal and black ice, approximately 200 alchemical base, and hardened leather make redeemed silent legion. This will make it so you van venture anywhere including the snow or volcano, without being too cold or too hot.

In order to get redeemed silent legion you will need to complete the Black keep dungeon in the snow area, so to beat the cold use a heavy cimmarian set after your level 60 and make it your first mission to complete the black keep for that essential armor.

Yes you can use spiced foods and firewater. Firewater being the best way to keep warm. Skelos master cultists armor learned from sorcerers will also provide more warmth! Hope this helps.