We have tried all sorts from putting hangers opposite ways to the foam you mention,only thing I have found to work is to hang everything up and then stuff a towel or similar between the top of the rail and the wardrobe ceiling
Never had any problems doing that and only carrying what you would be taking anyway
Wayne, take two hangers with the hooks facing each other so it forms a complete circle, and put an elastic band round the neck. pull the hooks apart to enable the hangers to be fitted onto the rail and hey presto! hangers that cant fall off the rail.
We used to have a problem with everything being in a heap,but changed vans and now have no trouble at all.Fold trousers in half over the hanger and clip the sides with a clothes peg.
Do buttons up on clothes so that they can't slide off so easily.Alternative is to pack all clothes in one of those under-bed plastic bags and hang it up when you get there )