Excellents answers by Mithelemir, just adding my 2 cents here :
B) What exactly are the prereqs for trigger the various events/chapters? Some of the stuff just seems to be timed, because I have a whole chunk of Book II and III quests active without doing much at all.
It's a bit complicated to go into details, but the best guideline is to try to finish your current wars, secondary quest and all timed stuff before progressing the "main" storyline quests.
For example, if you conquer London (Logres) to get your stronghold (I'm assuming you go christian, but it's the same quest structure for the old faith), Powys will automatically declare war. Beat them (and do all of the other stuff, timed and non story quests, possibly conquering other "small" nations like E/W Mercia) before starting the alliance with the Saxons quest (wrath of caradoc), as at this point wales with DOW on you, and you don't want to fight on several fronts. Fully completing the saxon alliance storyline will trigger a hard civil war event, so have the war against Wales well under control at this point (don't elminate them completely however, there is a risk to "timeout" the saxon alliance and go to war if you do so). This is just an example, but bottom line : be slow and cautious with the storyline quests.
C) Food: How to get enough? The AI seems capable of having incredibly large armies without suffering food shortage, but I certainly can't do that!
AI cheats
(but more accurately, many of the stuff AI do is quest/storyline based, not based on its economy).
Economy buildings in your strongholds, research, trading gold for food (you can do this during winter in the same screen where your set your policies), exploiting the "grain merchants", "millers guild" and similar trade quests where they spawn (offering a food for gold trade with an excellent ratio), selling your unneeded artifacts or damsels in trade quests (or using them in trades instead of gold/food when possible), lieges lords with traits/skills/wives/artifacts (be careful with negative traits, or culture/religion-dependant traits, eg. don't have wales ruled by a knight with a "proud saxons trait), boosting the leadership of your army leaders, garrisoning your armies when possible in reduced upkeep map locations (or stronghold with appropriate buildings).
And more importantly, winning battles with fewer losses, thus less replenishing costs, than what you get as spoils, keeping your units alive and experienced, and not using too many armies (1 in the early game, 2 for most of the game, an eventual 3 in the endgame). You can't garrison everything and try to be everywhere
lan your conquests, finish your wars before going further into the storyline quests, and have your main army(ies) as mobile as possible.
D) What in general is good stats to raise for your units and/or knights?
I use to max defense first for melee units, attack next, then stamina. Archery, then defense for ranged units. For the level 5 and 10 skills, it depends to much on the unit (but don't hesitate if you have more specific questions for specific units).
For knights, anyone leading your armies (usually a warlord) should have decent leadership (to cut down upkeep costs) and high adventuring (mobility is key, plus you'll get extra quest exp as added bonus). For vanilla campaign, I'd prioritize adventuring over leadership, for the druids/saxon DLC, you'll need to focus on leadership (in the DLC, you need to reach some leadership thresolds to allow a 2nd/3d/4th knight in your army, there is no restriction in the base game). If you use 4 knights in an army, only 3 knights at most are concerned, so don't hesitate to stack leadership/adventuring on them. In the harder difficulties, you might want a few fight points for survival (or cover this with artifacts)
Anyone NOT leading armies (all your other knights) will not spend a single point in leadership and adventuring, and focus exclusively on fight and magic (note that sages and warlords need both skills eventually).
A bit of reign (and liege based skills) for your best "ruler" knights (with positive liege traits).
For skills, it depends a lot on the heroes (each have individual spell choices), so I won't go into too much details (but feel free to ask specific advice), but as a rule of thumb :
- for warlords, masterful tactics (and associated subskills) is a bread and butter support ability, you can't go wrong with it
- for champions, well upgraded cleave and associated subskills is awesome
- for sages, many spell options are good (fog of death, dragon breath, many "morality" damage spells), but keep in mind you'll need some sort of mana regeneration - spellweaving is very good for this
- other notable skills if you have access to them : sunshine(researched spell) is a lifesaver in several mid-end game battles against ghosts and unseelies (or on the other hand, if you go old faith/tyrant, go with the nightfall spell and an army tailored to benefit from that), soul mirror is rare but absolutely fantastic, and sidhe roads (old faith spell) is so flexible and powerful tactically it's almost broken
Those are just quick guidelines, you can explore other skills, make effective warlords without the masterful tactics skill and such, but those skills will be well established and proven staples that will serve you well until you learn more of the game and be confident enough to devise your own builds.
E) How many knights are good for an army?
It's arguable, and I have seen people having good succes with less knights and more armies, but I'd go with 4 knights per army too, with an appropriately small number of armies with elite troops. I feel it more efficient to concentrate combat experience and cut upkeep costs. But you'll definitely have to be clever with your campaign map positioning and movement.
