To add to what has already been said,

1. Take tools to tighten every size bolt and nut that might work loose;

2. Have a spoke wrench to tighten spokes and bring a wheel back to "true". Even if you don't take the cassette tool, you'll likely need to adjust spokes neighboring a broken one to compensate for its loss.

3. If you're camping, be sure you can dismantle and clean your stove and patch your inflatable mattress.