Hey, sounds cool! I'll be following in your footsteps sometime mid-year. I too have a 2007 Trek 520, though I will be upgrading the tires to Schwalbe Marathon Plus tires. So far it's rode a dream in my touring training. Check out my site if you want, it's all about the planning atm, as i am not on the road yet.
www.bikevoyage.blogspot.com
Cheers,
kyle Archer