Only thing about Slipgear is that you will need to be at least in your 50's I would think to be sure you could run around all the Depths of Darkhollow zones. Most people did this quest around the level of 70. Corathus Creep, Undershore, and Stoneroot Falls are rather easy, but The Hive and Illsalin can get tricky because there are see invis and undead mixed in with the regular mobs, hence why you would want to wait until you have a group to go with you, or be much higher level to brave those areas.
You could probably do CC, US, and SRF sometime in your late 40's to early 50's, though. Which I think would still be a very decent charm aug.
Research TSS zones and quests, ie Blightfire, Stone Hive, Goru'Kar, etc. SoE actually did a really good job of populating that expansion with level-relevant quests with decent gear.
All of the times I've done Slipgear (admittedly it's been a while but I've run over 70 toons through that quest), if it wasn't a rogue, I used a goblin rogue shroud. All of the updates are easy that way. Rogue shrouds seem to automatically get rogue abilities when they open up (i.e. full speed sneak at 60, SoS at 62, etc). Probably the only good thing left about shrouds, honestly.
I don't know what Vox is like but keeping the tutorial BP until 57 on a melee class expected to tank? Wow, it must be harsh on that server. My newest cleric is 21 and I'm trying to hold off until 26 or so before using /claim and getting defiant pieces from there (Gift of Legacies Lost).
As far as can't miss quests, I'd put the epics up there. Sure, the 1.0s pretty much suck (except cleric) but it's a badge of honor. My Paladin at 87 spent three weeks doing Nature's Defender (Corruptor of Life is a....), and it went into the bank right after I took the screenshot
. Now I'm going to go back and do all the various other quests I skipped on her (SoulFire, Fiery Avenger, Fiery Defender, etc). And as an SK, you want your 2.0, there aint no doubt about it.
Some other quests that come to mind:
Jonas Dagmire's Skeletal Hand (which you could probably get done or at least start right now).
The Binden Concerrentia (fabled version is probably beyond you for now).
...now I'm drawing a blank. :(