If I have a truecrypt file on a shared drive, if I mount it by using the shared path does my password data get sent in plain text across the network? Basically my question: is it safe to mount a truecrypt file across a network without copying the file to your local machine first.
Your password data is not sent across the network, because the cryptographic operations takes place on your computer, in the TrueCrypt driver. The password is used to derive a key that is used on your computer to decrypt the encrypted sectors sent across the network.
TrueCrypt FAQ has a section on this. I beleive item 2 is what you want to acheive. Their warning is that someone looking at the encrypted trafic could get some side-channel information, like the amount of data read and written, and the offset in the encrypted file.
Unless you want protection from your government or other well funded attacker, I beleive you should be ok, password wise. You might test what happens when a network failur occurs while writing a large file. It might corrupt the file system you mounted.