Although I'm not a heavy road warrior, I spent my holidays abroad and found that I felt very powerless not having all the tools that I keep in my desktop computer. With that, here are some tips that I have picked up from my fairly extensive research on various GTD/LifeHacking topics.
1. If you use Outlook as your Contact Manager, I suggest that you take a look at plaxo.com. This is the only plug-in that I've been able to find that can completely sync the Address Book, Calendar, Notes and Tasks.
2. I'm still debating what I'm going to use as my ultimate task pad. I currently have a Cingular 3125 smartphone that supports basic task management. And I can sync this to outlook which syncs with plaxo. This allows me to make and manage tasks from any web browser which is sometimes more convenient than typing on the phone. Another option I'm looking at is just using either a small notebook or even index cards. http://hipsterpda.com currently has me fascinated. Sometimes it's easier and more professional to write things down than type into a phone.
3. Google's calendar is really good, but it's sync features with Outlook aren't as thorough as plaxo's. I use Gmail as sort of a journal though. You can also send sms messages to your calendar to keep track of what you are doing. i.e. Had a steak and shrimp. $30
Hope it helps!