If bicycling across China is what you've decided upon, you'd better take a trial run at home. Take all the equipment you think you'll need and try your best to approximate the conditions you'll be traveling under. If you can't approximate the conditions, talk with people who have done the same kind of trip. The Web is an excellent resource for tracking down people who have gone before you. A map each .
Good maps are expensive, but a map each is a good investment.
There is nothing worse than one person wondering where they are while the other puzzles over the map in their hands. A map of one's own can give reassurance. The other person may have the answer, and it's always better to figure things out together. This is especially good if you're traveling by foot, bicycle, motorcycle, or kayak. Life on the road will bring your partner's idiosyncrasies into high relief .