Physical preparation
Long and challenging expeditions require thorough preparation. Cycling a distance of 30 km three times a week is not enough - it usually takes one hour every two days, while during an expedition you cycle much more than that (in my case, an average of 6 – 8 hours a day).

In order to prepare yourself properly, start training regularly at least a month prior to departure. It is hard to discuss the whole issue briefly. Generally, you should cycle as much as you possible, supplementing the practice with swimming, stretching, and weight training, if you feel like it.

In order to avoid failing during the expedition (which is a rather unpleasant feeling), you really should not overestimate your physical fitness. If your trip is not going to be much of a sporting challenge, the exhausting training regimen is unnecessary, but then you should at least spend some time getting used to the saddle.