It is important to note that TOR does not provide added security. In fact, it could decrease security because you are funneling your traffic through exit nodes which could try to manipulate or log that traffic.
TOR does however help with privacy because it helps hide your actual IP address and therefore location / identity.
Running a full node alone will improve your privacy a bit over other types of "light" wallets (like Multibit) and if you follow the advice of
@makevoid above, you can improve security by moving your wallet.dat file to an offline computer. There are many other options for improving security and are easier to manage - look into hardware wallets and BIP38 encrypted paper wallet created offline.
how secure I am from other apartment dwellers
Anything running on Windows should be considered insecure. If you are using Mac or Linux, you chances of being hacked are much lower. Running a firewall makes sense as does using physical ethernet cable (rather than WiFi). The three options above (offline signing, secure paper wallet and hardware wallet) will all protect your private keys if done correctly.
I can leave it running only 6 hours a day
Running a full node will not help others on the Bitcoin network if you are only running it for 6 hours a day. If that was not your goal, then no harm done. The "6 hours" is arbitrary, you will just want to run it enough to keep it up-to-date (in-sync with the network) as new blocks are created every 10 minutes. Depending on your hardware and internet connection, this might require bitcoin-core to sync for just 15 minutes per day like my Macbook Air.