Try to mine first irons to build a longboat , its more efficient transport that the "hoe n cart " because almost all swamps have sea shores
For food until u get turnips and sausages : carrot soup , cooked meat and cooked neck tail , BUT if u re lucky to kill sea serpents : carrot soup , cooked serpet meat and serpent stew
Best weapon to manage all swamp mobs are the bronze/iron mace ,use anti poison me/ads and healing/stamina/tasty me/ads , try to make full iron armor and weapon tier before bonemass fight , become an easy fight if u do that