Sir @Gordon Nichols prepared an excellent post on "Spares for the Road" years ago.
I converted it to an Amazon Wishlist to make it easier to build my road kit. I think you all might make use of it as well. If you see something recommended that doesn't make sense, please let me know.
I gave the list to my family too so they can help me build my road kit over time. I'm hoping to make a significant dent in the list on Black Friday.