CDL at Varka or Ketra until you hit 78. If you have a BD and decent buffs, you can 2-3 shot the mobs, solid 2 shot if you have an AM w/Dark element and Major Arcana. No heals necessary. Side benefit is S Armor recipe quest.
Or you could go to IOP, mobs are 2 shot there, and get element stones. With an EE (esp w/PoW), you can farm dark water dragon shades.
If you have an OL to pull and root, you can CDL MoS.
If you have a meat shield or SE to root, you can CDL any catacomb.
Once you hit 78, you can kill mobs at front of Hellbound fairly easily, though they are dark resist, so wind only, and EE heal/recharges might be a good idea.
If you can get a few mages, a healer, a BD and SWS together, you can aoe FoG, Varka, Ketra, MoS, HS, TOI...
The higher level you go, the more XP is expected to be party based, which is why you are running into a wall trying to find decent xp spots. The higher level you go, the harder it gets to solo.
With Arcana Robe Set you should 2 shot most of them. You use Seed of Wind too, right? I was 2 shotting most MOBs there on my Necro when my mace was just 25 Dark Attribute with Arcana Robes. SH has Seed and more base P.Atk than Necro, so I dunno why youyou can't 2 shot at IoP with Empower and Zerk O.O
An SH with zerk+emp in DC will have slightly more matk than a necro with emp + arcana robes. With seed + slightly more element to begin with, something seems wrong there.
I'm a 77 Sts and yes the MP goes fast no matter what. You need buffs and a recharger at the least. I usually do IOP or Silenos. Like it was said the higher you are the harder it gets to solo. The game was designed for group play at that point.