You can do the dungeons (burial chambers) with a leveled up flint axe and basic level 1 leather armor as long as you maintain your food level. Go slow and keep backing out to the main entry room to let your HP recover.

After the first one, you'll get lots of bone fragments to start upgrading the armor. You need lots of the Surtling cores to build charcoal burner, smelter, and later portals. The other loot will buy stuff at the trader.