I've been riding regularly for 21 years and in addition to riding, I walk regularly ... and also ski, snowshoe, canoe, weightlift, do yoga, etc. etc., (but not as regularly as cycling or walking).
The daily distance I have ridden on tours is usually the same or less than what I might ride on a weekend day.
I don't change my cycling to train for a tour. However, most of my tours have surrounded 1200K randonnee events or other long distance events, and I do train for those by riding a lot, riding varying terrain, riding in various environmental conditions, and riding varying intensities.
In addition to making cycling part of daily life, I recommend doing upper body workouts. Most of my tours have involved heavy lifting at some point along the way, and sometimes quite frequenly. It is very handy to be able to lift and carry your bicycle, complete with your gear, at least a short distance whenever you need to.