this is a big question... and it depends on

- how new or "fresh" what you have now on your van
- how remote where you will be going and how long is trip
- how's your skill to replace a part if you have it on hand

the basic stuff such as:
- fuel pressure regulator
- dist. cap and rotor
- spark plugs
- Temp2 sensor
- set of belts
- fuel pump relay
- coolant
- oil
- Rescue Tape

others will add more stuff for sure