Pop up tent as a "shed" in which to put all large/wet/outdoor stuff.
Anything in the boot should be in large containers so they can be removed easily (and used as seats outdoors).
Duvets in the underbed locker help reduce engine noise.
Two types of food - wanted on voyage or not. The latter can be put away at the back of the cupboard. Lakeland tubs with handles avoids too much scrabbling about.
Tea/coffee making stuff handy - keep the kettle in the sink.
Completely agree about number of clothes - one set of warm stuff and maybe a spare if it is going to be wet.
We have ikea sleeping bags which zip up into cushions.
Consider changing the fridge for a powered cool box. I haven't done this but it wold give you another large cupboard and the new cool boxes are meant to be good.
Quick drying towels - from decathlon.
Folding silicone cookware eg colanders.
Hope that gives you a start.
