Another parking brake tip:
If you're running newer road caliper (the kind that have the lever on them to loosen the caliper so you can more easily remove the wheel), you can adjust the cable on the brakes as usual, but with the lever in the open, loose position, and then flip the lever to tighten the brake to use it as a parking brake. Very simple and easy to use. More of a theft deterrent than the velcro trick, as it's mechanically obvious what is causing the bike not to move in the latter case. When it's the brake itself, it's much less obvious (in fact, i often still fool myself). Still, you should just be using a lock if you're interested in theft deterrence. Working as a messenger, i've used this trick as a backup when i forgot my lock at the hang-out spot or whatever.
The obvious side-effect, of course, is that it's harder to remove the wheel, unless you're running thin road tires (unlikely on a tour). The other thing is that your wheel has to be totally true, or you won't be able to tighten the brake adjustment enough for the lever to actually stop the wheel. It works best on the front.