Paper mache tip for you.
Paper mache....I just had another idea for a catcave!I need to find a source of old newspapers as never get any my self, but sure my mom does so will have to ask her to save some for me.Maybe need to ask her if I can make the mess in her place too given not much room here.(She only moved a month or so ago and her place is super pristine newly decorated and all new carpet - but it is huge!) If the paper mache cave works I'll post about it for sure.
You need a big bowl like an old baby bath so that you can lie the sheets of newspaper out flat to soak. Leave them to soak for a couple of days so that when you try to pick them up they just disintegrate. When it's soft enough put the handfuls of newspaper through a food blender so that it turns to mush. If you mix a water based paper glue in with it the paper mache will set really hard. We used to mix that clear jelly-like glue kids use in primary school with it.
I helped make a huge paper mache dragon sculpture for Glastonbury festival one year, that was fun!