The game can be installed on a flash drive in the same way you would install the game if you used the TTP Demo method. The only difference is that with each computer you run the game on, it creates a small registry set critical to the game's operation before it starts. Literally all I did was run the OpenRTC2 installer, point it to a new folder on my flash drive and install, then extract the OpenRTC2 ZIP file to the flash drive's installation directory and run it.
This means that RTC 2 can be taken on the go, and the data is also saved locally to the flash drive the way the game is programmed by default.
The problem with doing this is that Windows 2000 and XP handle this game differently than Vista and later, and so the game will actually encounter an error and crash if you click the multiplayer button. My portable version seems to be the only version affected, but seeing as XP is stubborn with portable games, this was not a surprise.