Unrest hag room is a possibility, they're a pain to break but its doable if your gear isn't terrible (they get very slow at 40).
Basement isnt such a good choice, multiple mobs, some werebats etc make for inefficient non-undead nukes
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39-49 is totally spectres though if your mana pool can handle them, I'd go to Feerott as Oasis has that annoying water feature to negotiate (or root nuke the ones in OOT, guaranteed not to be camped, but remember to bind
[You must be logged in to view images. Log in or Register.]). Specs much easier at 44 (they die in 3 nukes).
If you really wanted, get to 39 however and you'll be in demand for many groups. CoM should be fast leveling
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