1. where does one view either of the jeys?
With the command line client, enter
bitcoind dumpprivkey youraddress
This will output the private key for "youraddress". I don't know how you'd do that with the qt client.
2. Is it necessary to back up these keys, much like backing up the .dat file that is your wallet?
The keys are stored in your wallet.dat. If you back up wallet.dat there's no need to keep separate copies of the private keys. Unless you want to print them on paper and store them in a bank safe or something.
4. what are some best practices/suggestions for guarding your private key?
Encrypt your wallet.dat and unlock it only when you want to spend coins.
