But I really like the vast dungeons. Quite some people actually hate them, but I love them. Eventhough the huge dungeons mean also a huge amount of the mindless combat

I normally hate the crazy-sized mobs, but some of them were interesting (defeating the Snergle's army wasn't nearly as mindless as the rest of the combat tends to be; and you can pretty much cheese the undead army in the Temple by running into the secret door and emerging at the side ledges, where the skeletons can't do anything to you).

Using the Prismatic Light against the Snergle's army is a cool idea... I remember dispatching the army with lots of tactical positioning, shooting arrows and casting tons of fireballs.

Dragon Breath is an awesome spell for the Castle Darkmoor, since it is a real eye-killer. One of those wipes out a whole bunch of eyes.

Cuisinarts are a good enemy type for those spells . It was hard for me to handle them with conventional weapons, but a couple of Mass Distortions and Petrifications got rid of them.

Shrapmetal works on everything, and all people here will tell you that it's the best attack spell in the game.

I usually do this in Blackshire, since the Master of Dark Magic is just over in Paradise Valley. First I cast Armageddon, then check my reputation. If it's still above Notorious, then I pick one to resurrect, slay it again, then check my reputation once more. Repeat until your reputation is Notorious; once I get Mastery in Dark Magic, then I Town Portal back to New Sorpigal, go to the temple, and donate until my reputation is back to Respectable. (IIRC, Donations there are in increments of ten gold, so I click Donate twenty times, as that's usually enough to atone.)

I disagree with the game's valuation of the different enchantments. My valuation is based on their usefulness in the game, and I found the most useful enchantments to be "of the Dragon", "of Darkness", "of Power", "of Protection", "of Plenty" and "of the Phoenix". In the next tier are the enchantments that couple regeneration of either mana or hit points with another benefit, and the "of x magic" rings.

But it can be perhaps made even more effective in the turn-based mode: when you see the enemies, pause, then shoot them, and if any of them get too close, do a U-turn back and only after that go back into the realtime mode. Then run like a bunny. Rinse & repeat.

So far I've taken on:
New Sorpigal outside excluding islands, with one bow
Castle Ironfist outside excluding arena and lizard infested region in front of Shadow Guild Hideout
Abandoned Temple
Goblinwatch
Misty Islands outside shooting the cutpurses from a mile away
Silver Helm Outpost - yes, it's strong but doable with a lot of running up and down the corridors avoiding the Captains and Master Swordsmen - faced only one Master Monk which I took out quickly with a good wand I had bought for the occasion (had a bounty on him as well) - my AC was about 35-40 on everyone so I could take a direct hit from one of the guards while dodging and running. I really dislike wasting days waiting for the right boat. Didn't go past the hidden door though, as it's tricky enough without the low levels.
Bootleg Bay outside as well as getting to that shrine just in time
Temple of Tsantsa using those trapdoors to my advantage
Free Haven outside excluding the archer mobs
Free Haven Sewers - my current spot avoiding melee fight with the thieves at all cost and trying to deal with one priest at a time.

Trained twice - to 4 in NS and to 8 at Mist - now eligible for 13 - planning to train after the Sewers.

But apparently your way works too, since you have quite a nice progress. I go to the Silver Helms early, too, first clean up the lower hall of swordsmen and monks, and only after that I open the door to the guard room right next to the exit, pulling the guards out one by one. The captain is a major problem, but I always manage to get rid of him somehow.

Also a nice idea to use wands to get rid of those master monks. That's actually something I could very well do the next time I play the game. (I bought some wands only when I was going down in the watery part of the Dragoon Caverns, with all those oozes.)