Bestest touring training regiment: http://ridestrongbiketours.com/begin...-cycling-trip/

Commuting day in, day out, will train you for the daily grind of touring. Add an overnight trip or two (3 days, 2 nights is better) to work out the camping and loaded bike stuff. My commute is 35km (total) and I often extend to 40-50km. A touring day is only twice or three times as long except I don't have 12 hours of "downtime" in the middle. Going the distance is easy. Engine noise, a stretch of bad road, cold rain, constant headwind, going to bed with layers of sweat, sunscreen and road grime, biting insects, getting lost, etc. Those are the real hardships of touring.