If worried about the cab doors, Sussex Installations in the UK has deadbolt locks that will keep those closed even if the windows are broken. I wouldn't want them on my "C" because they don't open from the inside. I personally wouldn't do anything other than a Jimmi-Jammer on the cab doors for safety reasons.
On the entry/exit door, I'd also look at a Fiamma Safe Door. It is a way to have security, but a tad more elegant than the mentioned hockey puck locks.