Talk Fantasy Football

Is it possible to do scenery using the ordinary styrofoam with the small balls in it or do i have to go with the more expensive version without balls?

Possible, yes. But the texture sometimes gets in the way, and tends to be softer, so you need some tough external coating. I have seen some with tiny bubbles that was stronger, but most have bigger weaker balls.

So expensive you can't get a plank of insulation? Pink, blue or whatever the color used by the local suppliers. If you have to buy something for the external coat, or spend time doing it (say wood glue and old newspapers), it could be similar.

Go with the more expensive pink/blue/green/purple/yellow high density styrofoam. You can work finer details into it without having parts crumble or break. Also, the finished product is far more resilient.

Make sure to glue the parts on at least a 5mm layer of wood. When applying glue on one side to add texture/grass/whatever it tends to warp as the glue sets. 3mm MDF will not prevent that from happening.

An old club member used it for hills (back in the day we played 40K *shudder*), but he'd covered it with a think outer layer of something after he'd shaped it, which he could put the correct texture on to. Unfortunately lost contact, so I can't ask what he used.

PVA? Lots of layers of PVA will keep it sturdy to a degree, but I would recommend extruded polystyrene (the pink/blue/green/yellow shizzle)

Take a bucket, mix equal parts PVA glue, dark brown paint and sand. That gives you a nice goo which could be applied and dries up to become a fairly sturdy protective layer on top of bubble styrofoam, but when you apply it it also takes away a lot of detail, if you managed to add any.

Plaster also works and you can carve and file and sand detail in to the plaster after it set and dried.