Chain of Events
A long trip will also accelerate wear on your belt or chain and sprockets. A broken drive system will at the very least strand you, and a chain that comes off could lock up the rear wheel. If it's stretched, tight, or worn, replace the entire assembly. If your belt has most of the recommended mileage on it, why not replace it before leaving? On the road, either system should be checked daily for wear and damage. If it's my bike, I lube the chain at every gas stop. I have heard all the claims about self-lubing chains and I know what kind of mess all that lube makes, but I am absolutely certain that all chains last and work more efficiently if they have lots of lubricant.