Definitly bring the air pump, if space is a concern mabye one of those mini co2 pumps will suit your needs.
Sombody was raving about a pump that was dual, c02 for quick inflation but also was a good regular pump incase you ran out of C02, thats the pump I want but i have no clue wich it was.
It would be nice to be able to ride with a friend as you can split the load for the important stuff that you both dont need to have.