No blocking needed for Bonemass, you cant stagger bosses anyways.

Poison res potion pretty much negates most of the damage, just get a mace and start swinging.

Originally posted by Rhapsody:

IMO it's a waste of time to explore mountains until you've gained the loot from Bonemass.

For first time playthrough yeah. But there are things he could find like seeds or caves. These are valuable regardless of progression. Also two good arrow type resources are in ample supply there.

Originally posted by Jaggid Edje:

I'm at the island with the bonemass altar thingy now, trying to find a good place to put ashore. It looks like the swamp here is surrounded by Plains....not going in there. It's a relatively small island so I'm hoping to find at least a sliver of black forest for docking...I'm not a fan of bringing my ship to shore in the swamp itself.

If you have root chest armor Plains are pretty ok to explore before finishing swamp... You can always make the mobs from different biomes fight each other to help clear things out (just dont get hit, and parry only with high max hp food).
But putting ship on plains while less dangerous than swamp can be a problem if you lure mobs to the ship itself, so make sure its not too far out so you can recover its materials in case of issues. And dont venture at night.