Thanks

I am thinking I will make a hole in the van with a deck hatch but also have the pump to grey option. That way I can dump in an area where it is allowed, but easily store it when it isn't ok. You could also put a water jug underneath to catch it.

The laundry basket was fine but I've only tried it twice. The curtain stayed inside fine.
https://www.amazon.com/gp/product/B075JCML16