1) Going into nether with full manasteel armour? = Suicide
You need full brass (fire protection) steam suit, with best tank, jet pack, thrusters and modular accelerator. Yes the steam jetpack is hell annoying to operate, but it's cheap flight you need to survive on nether surface. Also if you leave nether, remove jet pack from your suit it drains steam every time you are in air (Jumping, falling). But be careful if you miss click and take off the tank you will lose all the steam it contained.
But be prepared! It's still coal super hungry... You will need decent tree farm.
I also strongly recommend you extendo fist, you have extended range in which you can operate things, break blocks and
hit enemies. And Pulse Nozzle. It gives double jump.
For weapons against ghasts, you should get at least livingwood bow with infinite enchant or wand with shock foci (That's how I did it. Bow might be better if you know how to use it. Sadly they seems to never work against ghasts in my case... xD)
Later on use musket with bolt action upgrade.
2) Use the multi block boiler, the small one.. well.. ehm.. sux...
3) If you have enough mana to use manasteel equipment use ring of correction, it drastically reduces time you spend mining (you just hold mouse button and go forward)
and it detects silverfish nests (you will start hitting it with manasteel sword). Steam tools are fine, but you can recharge them only in base, and they wont last long even if you try to save the steam (not holding down RMB but clicking), also the need of using RMB can be anoying at first, but I easily got acquired to it. Then I had habit clicking RMB even when I switched to void tools... xD
4) Thaumcraft Horizons is awesome mod!
1. Use Liquefaction and Disintegration focus. They will make your struggling easier. Disintegration focus breaks items into crystallized essentia = no more taint from crucible and cleaner and faster way how to get essentia from alchemical furnace. Liquefaction focus cooks or melts items instantly. (it also melts stone to lava! After a while...)
2. Use Vat or Seroconverter for early->mid regen. You can get victius from leaves, if you break herba essentia in centrifuge or make Tainted blood pendant with regen effect.
3. You can use victius to clone meat (If you have at least one)! Food from leaves for days! How cool that sounds?
5) After you research Alchemical Transmorgrification (Witching Gadgets), use entropy crystallized essentia instead of cobble if you want to mass produce Alumentum in crucible.
6) Be careful, hungry nodes hurts... really... realy... hurts... T.T If you are sucked in, even jet pack won't help you... Learned that the hard way...
7) If you don't need leaves, use horn of the canopy, to get rid of them.
8) Personally I prefer Tectonic Girdle over Soujourner's Sash.
9) Low on vis? Put the wand in hotbar and go to kill mobs. They drops vis orbs. I never used normal nodes for recharging wand...
If there is anything else you would like to ask me, I'm all ears.