Sacred Haven of Debauchery

If you're not wearing magical gear (which is understandable, as the resistances are poor), just forget about pride and use fire arrows instead of other burning spells; you'll be much better off. There's no talk of "special effects"; these are normal spells, and the armor penetration based on level makes them effective. Just make sure to cast them with two hands (switch to single-handed weapons separately). Another option is the school of witchcraft. You can summon various atronachs cheaply and have them accompany you.
Most other schools seem overly complicated, but they can also be used occasionally as a small aid.