Usually you can complete most of an area before moving on. There will be a few instances of dungeons that are either clearly too difficult, or inaccessible until later on because you need a key or need to be able to fly / waterwalk to get there. There was one are that was a little annoying because you get a quest to enter a nearby castle and find something, but the castle is clearly WAY too hard, and you end up coming back there much later when you have a completely different quest to do in that castle, and the initial "find the object" quest is kind of like an afterthought after completing the more important quest.

For the most part I felt that the game rewarded the desire to "finish" areas because there's good stuff to find if you explore around. But sometimes I went to areas that were a bit too hard when I should have done some areas that were easier first. So don't be afraid to try traveling to new locations if you're having a tough time.

Many of the early-mid game dungeons (in relative difficulty) are actually found in the Bootleg Bay region. Temple of the Fist, Hall of the Fire Lord, Temple of Tsantsa. You may opt to leave out Temple of the Sun for later.
The sewers of Free Haven is also very easy.

Usually, you don't want to take on Gharik's Forge, Corlagon's Estate until you tackle those easier dungeons first. And don't even think about Snergle's Throne room.

The first time I played MM6, I stuck with the sweep and clear method. I would begin by killing everything outdoors. Then I would hit the dungeons. This made a few sections much harder than they needed to be, simply because I went to the wrong place first.

However, the second, third etc. times, I did a few things differently.

First, I found a Scholar and Instructor for my NPCs. The Scholar allows unlimited item ID plus %5 to XP. That means you save skill points, money and still get an XP bonus. An instructor gives another bonus to XP as well. But if you wanted, a banker or merchant would work well in that second NPC slot.

I found it useful to save some money and travel before exploring. Some quests are much easier and can be done early for XP and money without requiring combat (and don't forget the barrels and horseshoes you find along the way). Also the Misty Islands are easier than Bootleg Bay, if I remember correctly.

I also made black potions early for the stat boosts.

I like this approach where you clear everything! I noticed my party growing in power quite well. I have stuck with the guides as far as knowing which area to go to in what order ( something i think the game gives no clues about except saying that when you go west things get harder).

My approach was New S, to Misty, to Bootleg, to Freehaven, then down to Mire and that is where I am at currently. Ive only skipped Snergles in New S, and currently working my way through the dungeons in Mire. I have to say that the Temple of Moon in Bootleg was my hardest battle ever against the Minotaur King! First time I went up against him my cleric got one shotted, did a full buff and prayed and eventually came out on top (Uber vampiric axe for my archer to boot)!!

You are aware that enemies respawn after several in-game months, right? You'll clear out some areas and then you'll back to square one ;)

It's not "games of today" - I know I prefered this approach ever since I moved to PC in early nineties.

That said, the M&M games tend to force me out of this habit:
1) They frequently provide easy-to-access areas which are way too difficult for my party's current level.
2) Once you solve the early puzzles, almost the whole world opens up and you find you need to be present at about 15 different places at once if you want to complete all quests "immediately".

I have moved to a "get Fly and Town Portal (and maybe Loyds Beacon) with water mastery early" way. With that you can do the Obelisk quest pretty early and get dark magic with dark magic mastery early so you have more than enough time to get your reputation up to saint. I also do the easy quests like the first knight promotion or lord killburns shield as early as possible to get the XP and promotions. The statue quest is also easy with fly. After that I'm strong enough to breeze through most dungeons.

I'll have to say that ya having master water town portal is AMAZING! I've just finished up everything to the 4 crystals which I am now hunting for. Only dungeon i skipped up to kriegespire is the damnable castle darkmor... This place is still insane even with my party lvl 53... Stupid evil eyes, I find the only way to do considerable damage to them is to spam toxic cloud and seeing as i only have 1 dark magic user, takes awhile =(

Acid Burst works great too. (all kinds of beholders have 0 poison resistance)

So, that leaves only Knights and Paladins without any way to attack them with heavy ranged poison damage. For melee heavy party, it's imperative to first attack the beholders that get stuck to the elevated sides.

You sir are both a genius, and correct :D

Thanks, but I'm far from a genius, just a fanatic who completed MM6 seven times with different party combinations.

Parties I have yet to try:
---Only Knights and/or Paladins. --- (PPPP, KPPP, KKPP, or KKKP)
Great melee damage and healing (Heroism, Bless, and all Stat Booster spells), but no access to elemental damage of any kind except magic elemental. (and enchantments on bows). No elemental protection except Poison. Needless to say, Beholders will prove VERY tough ( Adding to that, I disallow Paladins to learn Master Bow!).

----Only Knights and/or Archers . ---- (AAAA, KAAA, KKAA, or KKKA )
No access to healing damage/status ailments, nor melee damage booster (Heroism or Bless, and the stat boosters), so fighting at melee is substantially worse than the party above. (Adding to that, I disallow Archers to wield two weapons of different types). However, master bow on everybody plus the occasional Acid Burst/Fireball/Lightning/Ice Bolt/Meteor Shower should make ranged combat relatively decent for most of the game, especially outdoors. And I can always use the teleport spells to heal up.

--- All Clerics. I suspect this isn't much of a challenge, and probably very boring game, racing to get Toxic Cloud , Shrapmetal and Dragonbreath ASAP. Only Oozes will prove a problem (immune to Poison, Magic and Physical), forcing you to hoard wands, and find enchanted Maces and Bows.

--- All Knights. Many have done this one but I only intend to do it after the three parties mentioned above. What NPCs should I bring along most of the time? I would say Healer or Expert Healer, alogn with a GateMaster or Wind Master whenever needed (the lack of Explorer or Pathfinder will make the game last long in game time , though)


Some remotely easy "challenges" I did so far:
KPPC: the cleric gave me access to most of the sorcerer's duration spells. I used Pathfinders/Explorers and Gate masters / Wind Master whenever needed, to get around. No access to Lloyd's Beacon was a pain sometimes.
AASS: I had access to Heroism, Bless, and Stat Boosters (Day of the Gods) via Light Magic, but no healing of any kind. So... heavy usage of Healer and Expert healer NPCs, from the beginning of the game all the way to the end.

I'd like to add that I ban elemental rings "Of ___ Magic" in my games, and magic booster NPCs, in addition to the Paladin/Archer weapon restrictions mentioned above.