I'll give you a number of solutions to this problem, and let you pick the best for you.

The simplest and most seamless is to do your computing in the cloud. No, not on an airplane, but using Web-based applications that store your data on a server somewhere (and hopefully back up that server). For instance, Gmail and Google Calendar pretty much guarantee that I can access my e-mail, contacts, and appointments from anywhere.

The problem is that this requires you to learn new applications. I haven't switched to an online word processor, so I can't expect you to, either.

Another solution is to keep the documents you use regularly on a flash drive, and just not copy them to your hard drive (or copy them there for backup purposes, only).

Or you can use software designed to sync the two computers together. Here are a few recommendations: