hi Ben, mine is fixed to batons of wood and then fix the batons to the van, I put some heatshield insulation between the van and the batons, if you're not going to put a flue on it then try and position it near the back door, you're also gonna need to think of a way to secure your gas bottle safely, either box it in or ratchet strap, my numbers on my website if u need any more help then ring.
Graham