This post doesn't intend to be anywhere close to the game itself. But taking in account the rules exposed before, let's check what kind of things must be taken into account in a rulebook. Any others will kindly be discarded into the primal void. When in doubt, for purely maniac reasons, i'll try to tend to the minimalism.
STATS: binary: you're either strong or you are not. There is no need for further gradation. If anybody could take down a door because is very weak, just roll to see if you do it in time. If the door is sturdy as fuck, only STRONG characters can apply. Equally with dexterity: every character is equal until there is a substantial difference where you can walk over tree branches like if they were a dance floor. Then we can say you're Dexterous. As i've seen, its done like that in Pits & Perils: they act more like allowing certain actions than as bonus (though of course they can still give +1's or whatever). We could see them as "skills" or "items" (ie: Dexterity is an object that allows you to walk over branches)
So in this case, abstraction is a YES. No need to know which PC would win in arm-westle, they can settle that fighting in person.
SKILLS: They can work binary too. You either know medicine or you don't. You either know swordfight or you don't. Maybe they can be mixed with stats in the character generator engine.
The main issue will be figuring out how to handle things that should stack with each other:
(skill: polearms and skill: strenght should stack when fighting? maybe only with heavy weapons? would that make them too powerful? we'll figure it out later)
MISSIONS: there must be a pre-written list or some kind of generator. The game is about hunting bandits and maybe stolen treasures, with potential plot twists. Hell, we can do a d20 table for 20 bandits, 20 stolen items, 20 things you know about them and 20 things you don't (your gm rolls here)
As I intend combat to be symetrical and as exent from GM fiat as possible, I need the character sheets to be very small so I can create enemies very fast and, if possible, randomly (so back to the previous point). I love random tables that have multiple colums that interact with each other and are fucking well intertwined to the point they generate cool shit that even its author is amazed at their oracular power. I have to figure out one of those. (abstraction here is a NO! workin hard is a YES)
CASH: I honestly like abstract wealth. It spares me from the work of figuring out how much a jar of honey and a quiver of arrows should cost, and comparing it to how much a prize should be worth for capturing a bandit alive or dead depending on his/her crime. Probably i should adapt this shit i made ages ago (Abstract: YES)
INVENTORY: I don't know when it was the first time I started considering the concept of quantum gear (basically, you have slots of gear on your inventory and when you're in need of something, you either declare what it is or roll to see if you have it. Maybe is after I saw a G+ guy called Joe Banner do it in a Dungeon World Lite game. I just loved it at first sight. Well, it doesn't work here, at least a priori. As I stated in the other entry, I want to make gear and its use the primary resource available to players to approach obstacles. Of course, a level of abstraction is inevitable (I can't cover in how many ways can a bubblegum be used ever). But there has to be a list of equipment. In fact I want various lists:
a) the common equipment that everybody can buy at the start
b) rare equipment that can only be bought in special shops (ninja tricks can only be found in ninja shops!)
c) treasure! Special or magic items are things that cannot be bought, ever. They can be traded for money or be kept around for their unique abilities.
In any case, their workings in game must be detailed enough so both players and enemies can use them fairly with the same rules. Keep in mind that the setting is not medieval, but rather a clumsy mix of feudal samurai post-whatever land filled with isolated mad scientists and that if the players find a gun that shoots ensnaring fishnets, there must be rules for that somehow: not necessarily realistic, but fair.
On Quantum Gear: I can see it on cases of micromanagement (whats inside a doctor bag? what's inside a roll of carpentry tools?) but no more. MAYBE make a case for "thief tools" but that sounds like the most overpowered object ever in a game like this.
(abstraction in here: next to none)
Also of course, encumbrance rules!
WEAPONS: Maybe something like (heavy/polearm/ranged/sword/close); or maybe taking the opposite approach and fully stat the most ubiquitous weapons in the inventory section (and, from there, all new weapons should compare with the stated ones). I don't want to get much into weapon distinction : If a spear has reach and does d6 damage, it works like that for everyone, and every spear-like weapon is functionally a spear.
Here comes the twist: the tone of the game is not deadly by necessity and bandits can be taken alive to the authorities. Making non-lethal damage must be a choice that PCs can take even with deadly weapons. Also non-lethal weapons like solid foam bombs have to be effective; and they might even double as unexpected tools
SCIENCE: Of course, players might not be able to accurately describe how they repair the robot, so a level of abstractness is required for that. I worked rules before for "quantum inventions" in which the players declared what they wanted to have worked on lately (a radar, a robot, etc) and it appeared on their inventories on a favorable roll. Now i'd like to make it different but still usable: maybe making them build it in causal order (state what you want, then spend time to build it) but reducing enough the building time so PCs can afford to stay overnight in an inn and spend piles of junk (a buyable item) to craft an infravision glasses (you could also buy them in a shop, if you find one, of course, and spending much more money!). A PC that can craft shit is much more useful if the game encourages inventory as the great equalizer, so I'm greatly interested on seeing if this can work. Also probably I should differentiate between types of Crafty Guys, even if they end up making the same shit and role (medicine man and clockwork man are different things, though they use different reagents. Maybe the doctor can also brew an Infravision potion. I don't know. Maybe there can be still lists and crafting a substitute for something that is in the other guy's list is harder to do and works slightly different. I don't know yet. But as this is tied to inventory, the rules should be very tight!)
So, for now the booklet consists in:
* Character sheet (SKILLS+INVENTORY. If there is HP or equivalent, it should be tied to "time since you have been adventuring" or other level sinonym, and could be use as a way to add granularity in a combat where two Swordmen fight one against the other)
* Skill list
* Inventory list
* Secret Inventory lists
* Rules for crafting more inventory
* Simple combat rules that add nothing to balance the fights to the PCs side
* Mission generator