This is why I haven't made the plunge to hard mode yet. I fact, I think I'm going to need to increase the size of my buffer zones around my base. Dungeon brick is still pretty much uncorruptable/unhallowable, right?
Pretty much all the brick will remain untouched, from what I've seen, not just dungeon brick. Wood, too.
Most of the stuff in hardmode (at leas ton the surface) is fairly benign if you can stick it behind a wall (though possessed armors will open doors -- the old platform-on-inside-of-door trick fixes that.)... with two notable exceptions. That being the wraiths, which go through walls but are fairly easy to kill (slow, no ranged attack, about average HP for a hardmode critter), and wyverns.
Wyverns are a bitch if you don't have room to maneuver, though they're fairly easy to deal with if you can move around a bit. They noclip too, except they're huge (About the size of a world feeder, which is to say larger than a devourer), fast, hit like a brick, and have
4k hp. Think flying world feeder. Wyverns
generally only spawn if you go up a bit, around sky island level, but sometimes they make an exception.
Hey can someone be a real pal and write a very condensed "To Do List" that vaguely outlines all of the stuff one must do to get at the new content? My friend's gonna be putting his server up tonight and we wanna start from scratch and get back to 'being done' as quickly as possible, without having to check a wiki to see what we need to do next.
So basically just say where we should be looking for the next 'thing' rather than describing what the 'thing' is.
1. Go to Hell.
2. Fry an annoyance by demon-obtained proxy.
3. Shit yourself and die.
4. Come back prepared, kill thingy.
5. Get happy message, go to surface, get raped by laser snails and unicorns.
6. Talk to guide, realize you need to go smash an old fangy friend that you once couldn't smash.
7. Harvest the insuing gifts, make weapons/armor, use crafting help to figure out what to get.
8. Reach the point you can start summoning the hardmode bosses.
9. Summon one.
10. Shit yourself and die.
11.
12. Profit.
Some reactions may not be as extreme as described, but they give the gist of it.