Hi, I'd be surprised if a GPS would work inside a container, but I suppose you're thinking of tracking it down after being stolen.
Containers are very secure, how about just putting some 3/8 D70 chain through both rear wheels with a big lock on it? Thieves generally aren't all that ambitious (otherwise they'd be working like the rest of us) and I think the extra chain through the wheels would be enough for them to give up and look for an easier mark.
On my little farm back home (I work on the opposite side of the country for most of the year), I put nice barbed wire fences, with ordinary farm gates at both road entrances, then heavy concrete blocks with locked cable gates about 100yards from the cottage. I haven't had a problem since, but the b*****s broke into my place twice before that, when it was easy to drive into.
Now they have to stop at the farm gate, then stop at the cable gate, and they could be seen by neighbors at both stops. I'm a very good neighbor, and I think they take care of me and keep an eye out.
I've also thought about getting a container though...
Good luck with your place!
Bye for now,