My ACKS game is kind of coming apart under various pressures, but it's shown us a lot about the system itself. In this particular case, we had a few 7th-9th level PCs with early domains who were pushing for hex-clearing to be the primary activity of the campaign, and largely succeeded in directing things that way. What we ran into, though, was that hex-clearing for a party of 4th to 7th level (as the rulers were frequently non-participating) was both difficult and not all that rewarding, since there were a great many low-yield beast lairs like giant catfish and crocodiles, while most of the remaining ones were medium-yield high-danger humanoid villages, occasionally backed by spellcasters (as they discovered to their peril while plotting a morning raid against weaselmen). There was much boredom and frustration, and many grievous injuries and henchman deaths. When brought to discussion, part of what came up is that "going through places and killing everything there just isn't that interesting." And this comment brought to my mind a more general distinction in playstyles which is present in ACKS.
When dungeoneering at low levels in ACKS, you're not out to clear the dungeon. You're there to find and steal treasure, because treasure gets you XP, and fights are generally to be avoided because they're dangerous. Generally fights in low-level dungeoneering are a result of either a careful risk-reward calculation ("We hear what sounds like a snoring dragon on the other side; I vote we chance the fight because we have surprise and dragons have good treasure"), which is the unusual case, or the result of something going wrong - a bad random encounter check, negotiations going poorly with a group that were thought to be friendly, poor exploration technique, or what have you. Those are more common in play than the first type. This type of play I will term "resource extraction"-motivated; the party is in an environment seeking a particular resource, with fights being incidental and not the aim of the endeavour.
What we saw last semester in ACKS was a shift from extractive play to conquest-driven play. The first two sessions last semester were the Conquest of Fort Camarone, and centered around clearing an abandoned Zaharan fort for use as a forward base, domain seat, and trading post. All of the inhabitants of the first level were either slain or brought into the service of the PCs, the level was fully mapped, and the entrance to the second level was fortified to prevent things from getting out (mostly). This was a very different style of play; whereas normally a dungeon lair of humanoids might be bypassed as "too dangerous for the treasure they'll probably have", it was now imperative that the threat of the lair be eliminated. More fighting and less emphasis on treasure ensued. It became somewhat reminiscent of a 3.x dungeon crawl, where, since the only source of XP was killing monsters, you wanted to kill all the monsters because that was what the system mainly rewarded.
It was an unfortunate turn of events that this dungeon-clearing operation happened just as the semester started and we picked up three new players, who were never exposed to ACKS dungeoneering in the low-level style. I suspect that this group of new players in the conquest mindset, combined with the focus of the players who had domains on expanding their domains, was what led us into conquest-driven wilderness adventuring straight from dungeoneering. And it was there that we started having serious not-fun, which was further aggravated by hijink hijinks on the parts of some of the party and late-surfacing issues with the Venturer class. And so the game goes on hiatus.
But, the upshot of this whole process was the realization that, if dungeoneering can be done in both resource extraction and conquest modes, wilderness play probably can too. Once I realized this, it dawned on me that I had in fact run one session which was just such a wilderness adventure in extraction mode, and this was the Expedition to the Crocodile Temple. In this particular adventure, the players had been informed by a treasure map that there was a valuable treasure to be had in a particular place in the wilderness. They went to go extract that treasure, and any fights along the way were either accidents (random encounters) or against the treasure's guardians, well-justified by the expected value of the hoard. This revelation also made ACKS' "treasure maps as treasure" mechanics make more sense. Previously I'd mostly had treasure maps point to full-blown dungeons, but that was rapidly becoming infeasible due to elevated PC levels and prep time constraints. Having maps pointing to high-value lairs as drivers for expeditions in the mid-levels is a much more sensible solution. This means that mid-level parties should generally avoid tangling with low-value lairs like the weaselman village or the river full of giant catfish, and focus instead on large, high-treasure monsters like dragons where the party can focus fire, probably win via 3rd-level arcane spells (I really feel like d6 / caster level is where you start to get into proper Monster Killer spells that can take out real beasts), and gain large enough treasures to earn significant quantities of XP (part of the issue with knocking over crappy low-value lairs was that nobody was levelling, which made people grumpy).
Further, if this strategy is pursued at mid-levels, then by the time the party reaches name / domain levels, there will be 1) fewer lairs in the vicinity, since some will have been cleared in expeditions, and 2) the remaining lairs will be mostly of either humanoids or animal-intelligence creatures with no treasure. The former poses significantly lower threat to 9th-level characters than to the 6th-levelers we were trying to take them out with (even given equal mercenary backing); a trog chieftain is about the equal of a kitted-out 6th-level fighter, and has a decent chance of winning a one-on-one fight against such, but is unlikely to win against a 9th-level fighter due to superior hit points and to-hit and probably better magic gear. The latter category, giant animals, are generally not horribly dangerous (relatively), but there's just no compelling reason to kill them off unless the domain ruler is offering a bounty, you're the domain ruler and want the hex cleared, or you're sick of the random encounter result for that particular hex being giant spiders. They're also much simpler tactically to deal with via mercenaries, area spells, traps and bait, and similar tactics which are readily available by high levels.
The other realization I had on this topic is that the trade rules are probably meant to be used in this mid-level range. The party is supposed to pool cash, buy a boat, and start travelling as a group with the twin aims of reaching faraway high-value lairs and moving goods at a profit. At least I think this is how the ACKS trade rules are supposed to be used; as a supplementary income to lair raiding for mid-level parties capable of dealing with wilderness random encounters, and therefore able to travel long distances. Unfortunately, we were using trade as something more like "hijinks for the rest of us", where the party invested in autonomous caravans or the venturer PC's merchant company, and those went off and did their thing and many many die rolls later came back with a bunch of money. This was the wrong way to play it; I should've been rolling random encounters for each wilderness hex traveled, which would likely have brought the PCs out into the wilderness in defense of their assets.
My conclusion, then, is that we accidentally skipped a 'phase' of the game. OSR games are notable in that their gameplay changes significantly in manner and motive over the level range, as compared to 3.x / 4e where at first level you're fighting monsters in a room, and at 20th-30th level you're fighting scarier monsters in a bigger room. In ACKS, though, what I'm seeing is more like:
1st-4th levels: dungeoneering. You don't have the firepower and durability to take out wilderness encounters, so overland travel is probably a bad idea.
5th-8th levels: your wizard picks up fireball and the wonderful world of overland travel is now a lot safer. Your thief and a few of his buddies start pulling treasure hunting hijinks to get you treasure map locations, the fighter leads the mercenaries, and off you go to fight dragons and other fun critters while avoiding the annoying crap like weaselmen whenever possible. Optionally, engage in trade for a bit of extra cash or, if closely-affiliated with a local ruler, possibly pursue bounties for annoying critters that he wants out of his lands to get in good enough with him to get a grant of land when you hit 9th.
9th+ levels: the domain game, conquering hexes, realm politics, guilds, ???
And we made the mistake of skipping that middle one... Definitely something to remember for the next campaign I guess.