A caravan can be constituted-of-or-filled-with (police vans).
A caravan can be constituted-of-or-filled-with (television trucks).
Caravans can be constituted-of-or-filled-with (four-wheel-drive vehicles).
A caravan can be constituted-of-or-filled-with (tv satellite trucks).
A caravan can be constituted-of-or-filled-with (motor homes).