How can I mount a drive with Truecrypt through a script based on its UUID?
Here's a quick and dirty guide to specify the mount point based on the UUID. It works in Linux and since OS X respects fstab, it should work there too: http://www.cyberciti.biz/faq/linux-finding-using-uuids-to-update-fstab/

Note: You might have to modify it a bit as some of the entries specified are not used in OS X. Give it a shot.

Additionally, I'm wondering if you could just change up your script to pull the device name instead of the mount point, that is, use the device name (e.g., /Volumes/YourDrive instead of /dev/rdisk1s2) as that never changes (unless you rename the drive).