Natuk is an annoying game.
Every fight so far has been a cakewalk, and then the Hobgoblin chief and his cronies defeat me soundly. It's like suddenly the Withdoctors' spells are more effective (they never Stunned any of my guys before), the big hairy apes suddenly are more dangerous and the chief himself brains my guys in one hit.
Should I have explored the the old tomb first?
My memory is sketchy because I am old but I will try to recall and post here a list of dungeons and their difficulties and preferred order of doing...
Cleaning out the rats is of course the easiest (you can jack up difficulty to 500% and then use 'Q'uick combat for most of the fights. Keep the silver nuggets you find and sell all but one of them to a shop before talking to the main leader of the outpost (who will take whatever nuggets you have and give you some spell books as quest reward)
After you finish the rats at some point will come an attack by goblins onto the outpost. This one is not hard but I would not use quick combat.
After (or maybe even before) you beat up the attacking goblins head to Klorga and get the quest to kill that little old guy in the outpost ('Shuvoth' I think ?!). This same guy will also heal your party for nuggets (which no one should ever have to do). After you kill Shuvoth (or whatever his name is) and go back to Klorga to talk to that wizard guy (he sells spellbooks, staves etc.) he will give you a broken suit of demonic plate mail you can repair (if your skill is like 160-180 or something).
Next go kill the goblins (don't forget to improve skills/attributes with experience points first). I would put off the stirges and gnomes for a bit IIRC as they can be a pain for lower level parties.
Remember to use the stealing skill of your scout to pilfer weapons (from that green-pants guy in the outpost who requires the secret password you get from the little kid), armor etc. in between dungeons. You can save and reload shop inventories if you are into that.
At this point the Gnomes should be doable though you may have to make a few return trips to town to get more gear (by stealing it).
After that either the stiirges or hobgobs should be doable. Remember to sell and acquire new gear. I tend to trek all the way back to Klorga for this as there is more shops and also a guy who will give your party members experience points for like 500 gold for 10 pts. Remember to buy up any of those spice and incense and use them to boost magic and prayer skills before attempting to cast 'charm' and/or 'fumble' (just so you can learn those spells permanently and have them added to the spellbooks). Both spells are almost a necessity to beat tougher opponents. Fumble, after repeated castings on a single enemy will effectively paralyze them for the combat.
After you are able to catch charm at least once or twice per battle (using incenses to boost prayer if necessary) you can more easily tackle hobgobs, gnomes, giants, ogres etc.
Save those undead to the northwest of the outpost until you can 'Mass turn' them with some success.
I am just now noticing you have already discovered much of this and are at the end game so I will shut up for now...