Window tint won't work as the polycarbonate gasses out placticisers and will bubble the polyester tint. Tint film won't stretch around the complex shape either, not without liberal application of a heat gun, and that heat won't do the transparency much good either. All the UV protection in tint is in the glue layer, so don't expect it to last very long either.
Vinyl wrap from a sign writer will do the job though. It will stretch around the complex corners and look nice. There will be a chice of colours to match the door or other decals on the van.
It will also come off again in a couple of years if you want to sell the van in its unadulterated state.