We're like LakieLady - keep the van stocked all the time (just milk, cheese, wine to put in the fridge). We each have a small storage box for our clothes so it's easy to chuck a few pair of pants and weather suitable changes of clothing into the box, and we're off! Everything inside the van (including the storage boxes) has a place to go, and must be kept in its place. For us it works because it's about living simply, a couple of plates, a couple of pans, a mug, a glass, nice food that can be cooked on 2 rings, solitude, a view.
Our house is full of 'stuff' electronic gadgets, cooking equipment, hobby things, more clothes / shoes etc than we need. It does get used, but it also take up a lot of space and gets messy. In the van there's no room for 'stuff' and no room to be untidy, and strangely in the van everyone puts things away properly (which doesn't happen in the house!). Last weekend the weather wasn't great but we went away anyway. On Sunday morning it was unexpectedly sunny and there was a huge delight in sitting outside in the sunshine drinking my breakfast coffee and enjoying views of grass and trees.
We have a heater for colder nights (or spend the evening in front of a fire in a nearby pub) and in the winter we use the van to enjoy getting outdoors on day trips - it's wonderful to end a windy, squally walk by getting into a dry van, heating up a bowl of soup and reading a book.
We're very lucky in being able to keep the van in our garage.
But yes, it was a big expense.