1) A mirror and a magnetic pickup for inspection is useful, goes along with the flashlight etc you already have.
2) Spare fuses, electical tape, etc.in case something simple but stupid were to happen with wiring or electical (like obvuiosly frayed insulation).
3) Adjustable wrench+combos 8mm up to 14/15 or whatevr for that make/model is good. Don't need to be expensive, just decent and have fitments that are correct.
3) LN-6 Pliers or similar, maybe Nose plier, mainly to reach and pick up a dropped tool/nut or whatever, avoid touching stuff that is hot. Pliers should have a crude enough wire cutter so dikes are probably overkill.
3) pair of nitrile, gloves and some rags etc.
4) stainless baiing wire is very helpful with more 'stupid' fixable w/simple hacks, like exhaust hangar or other bracket-breaking.
Basically I think of roadside tools as enouh to get you to the nearest town/napa/wall-mart and maybe then to change oil/fluids, swap a fuse, fix a flat etc.
Anything more than that is credit card + auto club and long-range towing etc. Just pay the fees, totally worth it, especially if driving home for breaks/holiday etc over the next couple of years.
5) Changing sparkplugs is probably at the limit here, for example, but maybe consider if that is worth the hassle to even think about.
An ounce of prevention is also worth a pound of cure...so make sure the care is checked out before leaving and that more easy fixes are sorted out early...hoseclamps and that kind of stuff...you should be probably inspected and swapped out ahead if major issues seem lurking.
