Headset wise you can use a wrench to set the threaded type before you leave, if it ever loosens, you can retighten by hand, it loosens up again, and you adjust it by hand it is good for 100 miles or so, you can even do it while moving. I use the threadless style for other reasons, but as a repair item it wouldn't be on my list.
Phill hubs do just use allen keys for disassembly, and in addition the cassete bearings and the hardened axels are so bulletproof you probably won't need to deal with them. Same goes with, phil BB, and Chris King headset. Apparently some models of phil can be set up with just one spoke size for front and back hubs.
The other obvious point is that one tool you can use for many things is no burden. If a particular part needs a wrench you will be carrying anyway... The reverse is that some parts use the wrench you will be carrying anyway, but actually need a much heavier version than you will likely carry. Your 15mm cone wrench probably won't remove your pedals, and the little 8 mm wrench in a pen knife key set won't take the click out of you crank arm, even with a go-bar.
I use standard road pedals, like from the old days, and I attached a very thin layer of SS over them, bent front and back and attached into the toeclip holes. The result is platform pedal comfort without a lot of weight and with good serviceable bearings.
Without going to heroic lengths, I think one sometimes has to look outside of the regular tool supply chain. Tools tend to fall into 2 categories, so small, nasty and weak they don't work, or the bike shop grade, but the size of a boat anchor. I think that making one's own tools can create certain tools at a better weight strength ballance.