If you're daring enough to go to the Underworld, you can get hellstone (and a HellForge) for a Imp Staff. If you want to keep at it, Molten Armor gives only melee buffs, but also has the highest defense pre-Hardmode. While you're at it, you might pick up a Demon Scythe.
An early trip to the Underworld is going to be much harder if you don't already have a Hornet staff. Without that, every time an Imp shows up, you'll have to fend off their shots and wait for them to teleport near you. Bring as many buckets as you can, some of them filled with water. The idea is to keep in close quarters as much as possible, siccing your Hornet on Imps and being prepared to hammer on Bone Serpents. Now, Obsidian Skin potions are good for backup, but if you get careless mining with them, you'll spill lava all over the place, and then when the potion wears off.... So focus on keeping the lava contained and away from you, even if you do have the potions.
Whenever you enter a house, add blocks and doors to close off any gaps, to keep out wanderers. Knocking down and replacing the walls might not be a bad idea, but you do want some drops too, so it may be better to fight occasional spawns indoors. Look for where hellstone and ash runs up against the house. Carefully mine through walls and ash to get within reach of Hellstone veins (Extendo-Grip or Toolbox is good), and choose which blocks to mine so that the half-buckets will combine into a full bucket for you to scoop. Mining out drains and pits beneath the Hellstone can help too. If you get an odd bit or thin layer of lava that you can't scoop, use the water -- it won't stick around, but it will still quench a tile or few of lava..
And of course, remember that if you do get killed, you still keep the Hellstone you've mined so far, and you can do multiple trips.
