I do the opposite of Raybo... I spend almost all my time on my TCR year around. My touring bike is dialed in for fit and is ready to go when I am. I sure don't fill panniers with junk to train for a tour either since I know it already works well and how I will pack it up. If I want to get more fit I turn the pedals harder. Watts are watts and having saddle bags full has nothing to do with that. I do intervals and recovery rides when on the road. I also do fast group rides with my local buddies.
Base miles are just that.. Build a strong base on whatever bike will get you out and riding and having the most fun.
And yes I would suggest building up the miles before a tour. Plenty of people start a tour out of shape... It can be done but isn't much fun when the first week starts on the West Coast headed East.
If you want to practice on the touring bike I would suggest finding a campground about 50 or so miles away. Load up for an overnight and do just that. Little shakedown cruise never hurts before you leave.
Last edited by kayakdiver; 03-19-12 at 03:47 PM.