I'd like to encrypt the system drive on my desktop computer, but I routinely use it remotely so I don't want to be stuck putting in a password or USB stick on boot. My primary concern is with someone breaking in and stealing the computer, I'm not really concerned about a targeted attack or my roommate trying to hack into it when I'm not there or something like that.
My thought is that I can store the key somewhere outside of the computer but still automatically accessible inside my apartment. That way if it leaves the apartment it no longer has access to the key and it can't be unlocked without manually entering a PIN.
Bitlocker Network Unlock seems like it would be perfect for this, but it requires a TPM.
My current best idea is to get a long USB extension cable and put the key on a USB stick that's glued to the inside of the wall or something. Someone that knows the setup could easily just grab it along with the computer, but odds are the average thief would just yank all the cables and walk away.
Are there any better options for what I'm trying to accomplish? I'm running Windows 8.1.