Good place to stash a safe on a "B"?

I looked at those, and they are fairly big, especially for a "B". Instead, what I might do is see about using the safe I linked to in the original post. That way, there isn't going to be damage inside, but outside when a would-be thief tries to saw off the strongbox attached to the tow hitch, which is generally easier to deal with.

So far, I've found one brand of storage that is up to snuff, made by Fort Knox Safes, but their strongboxes are sized towards firearms.