Rem505,
I have been on some mil ranges that had stationary hulls of (wrecked/shot up) vehicles that were used as targets. We used these ranges for anything from heavy mounted weapons on a vehicle (or dismounted), mortars, call for fires for certain things...
Point being, with a wrecked vehicle, it is an accet in the game and can be placed in. Since not a useable vehicle, it doesn't have a "condition" that has to be reset between uses. With pop-up or moving targets, the same "material" of the target can be usefull for using a wrecked vehicle hull and by not having to reset the target. I would suggest using the earth berm/ramparts? to wall up in front of and protect the tracts and target systems from damage (assuming that damage may make the system not work anymore).
I hope this gets some ideas going for ya.
For a remote target activation system to activate the target, not too sure about how to create that on the game.
Let us know how your idea pans out for ya.