BTW, the HP regeneration associated with high Constitution was only in the original editions of AD&D.

Third Edition rules, as seen in IWD2, no longer provide such a perk, so getting no regeneration (well, properly, it would really have been "fast healing" as in 3E, "regeneration" refers to a very specific mechanic that is far more powerful than merely auto-healing HP over time) is normal.

However, the overall trade-off is still that high CON in 3E is more powerful in the long run than it was in old AD&D; all classes now get the full HP bonus from CON (although your Barb would have anyway as it's a fighter type), it grants a bonus to arguably the most important saving throw in the game (save or die effects in particular are usually Fortitude), and since Name level was abolished, you now get the HP bonus from CON forever instead of just for the first 9-11 levels :)

Just out of curiosity, how much real life time to you spend on battle squares? I find battle squares the most tedious part of the game so I just enable the cheat keys and kill the monster outright. Considering that the outcome of battle squares lies solely with the random number god and not my own actions, I'm not adverse to this kind of cheating,

However, to do battle sqaures with a solo barb, you must be the worlds most patient person.

It probably took a few hours or so, split it up across a few sessions.

I didn't have much trouble with it, just quick saved after winning a square, the only enemies that I had trouble with were the ones who sometimes teleported away, if this happened I just quick loaded, luckily it didn't happen very often.

I was able to kill everything that appeared in melee, sometimes taking quite a bit of damage but have plenty of potions as well as a couple of regeneration items for healing.

I enjoy the style of combat in these games so didn't mind the battle squares. The items and exp make it worth while. Selling the items I won but don't need was worth a lot of gold.

Have finished the wandering village and fell wood areas, been a fun chapter so far, the dark treant fight at the end of the woods was a pretty tough fight with it been in quite a small area. Only got lost a couple of times in the woods. Got plenty of gold still even though have been buying everything of use, including almost filling 3 potion cases with potions.

The first area out of the fell woods has been interesting so far, I was expecting an easy area but instead encountered a spider army followed by a larger spider army followed by a troll army then barbarians and wyverns to finish with. Weapon arm is tired now. The narrow lane between the boulders that form the gate was perfect for funneling the wyverns and barbarians in to reduce the advantage of their numbers.

What level is your barb at now?

Was he able to complete the 8th chamber in the monastery okay?

At level 20 now, at the start of the area where you meet the first dragon. Haven't reached the monastery yet, which chapter is that in?

Just killed the white dragon and white wyrms outside of a cave entrance.

Stood off to the left of the entrance where they could only get to me one at a time, ended up been an easy fight, minimal damage taken.

The second dragon and wyrms inside the cave made for a bit of a tougher fight with having to go toe to toe with the full group but defeated them with a decent amount of hp left.

The Duergar have fallen. There was a lot of them but when funneled into a doorway their numbers didn't help them, just made sure to take out any clerics that came into view.

They do drop some useful items.

No moments like that so far, there have been quite a few very tough situations but there was always a solution.

I've found using the entire area and picking the best spots to fight in really helps, like with the duergar I attacked them then lured them to one of the doorways to the rooms that had hook horrors in, and held my ground there only ever facing two in melee at once. When entering a new area I keep a lookout for any good spots for fighting larger groups, and fall back to there if I encounter any. If there aren't any good spots for this then hit and run tactics tend to work well, trying not to get surrounded.

What amazes me the most is the OP asked what chapter the monastery is in. In other words, "my first play through of IWD2 is with a solo barb". Normally, solo play throughs are self imposed challenges but I guess the op doesn't doubt his hardcoreness ;)

@OP

The monastery is in Chapter 4, if you aren't there yet, you should be very close now. I won't much more than this because I'll be entering spoiler territory if I do :P

I prefer playing these games with a solo character rather than a party, have played BG1 and 2 and IWD solo.

This character is technically my second, my first barbarian I played up to just after the prologue and was more of a tester to see how this game differs to the previous one, made some tweaks to the character creation based on what I learnt and started this playthrough. Such as wisdom been important for will saving throws as well as dex and con for other saving throws, this is different to how it was in IWD.

A single over-leveled Barbarian is really powerful.

So it seems.
My own experience is limited to using barb as a multiclass component (where it works real nice) and watching Daelan Red Tiger in NWN 1.) failing to hit with the stupid dual axe 2.) getting hit a whole lot due to low AC and 3.) running away scared after failing his will save.

1) Yeah, the double-axe is doing Daelan no favors. It works out to about the same damage as a greataxe... except Daelan takes an attack penalty for "dual wielding" so he hits less often and he needed to invest several feats to actually be able to use the weapon effectively. Feats that could have been used on more useful things. It's sad, but even with all his feats tied up in dual-wielding he'd actually be more effective by just equipping a greatsword.

2) The AC issue isn't nearly as bad as it sounds. Killing enemies before they can deal too much damage back to you is a perfectly valid survival strategy, and one that Barbarians are well suited to. It's also made easier by the Barbarian's massive hit point total. Given how generous the D&D CRPG's are with resting, recovering those hit points if you do take damage isn't hard at all.

3) Barbarians do get a will save bonus when raging, so he's actually better off than the Fighter, Rogue, or Ranger in this regard. Like most martial characters, though, he's dependent on magical buffs to get through these sorts of issue.