In the past when I've stored vehicles over the winter, I've made sure the tires were fully inflated, and that was about it. In the spring they were flat-spotted but that went away after the first few miles. That could be avoided by putting the vehicle on jackstands, I suppose. Jackstands would also protect the tires from damage if they leaked air over the winter.
If it's outdoor storage, cover the tires to avoid sun damage. Most RVs have their tires killed by the sun long before they run out of tread.
Don't set the parking brake, the shoes will probably rust to the drums if you do.
Don't leave any food in the van, even in sealed packets. The mice *will* find it. Then they'll shred your seat padding to make a nest. Been there, done that.
In the past I used to use a fuel stabilizer, but modern fuels are pretty stable so I'm not sure that's really necessary anymore, especially with modern evaporative emissions control systems.
Use a battery tender (solar or plug-in) if you can. If not, probably best to disconnect the battery. If parasitic loads cause it to go dead in storage it can freeze and burst. Been there, too.
Check the air cleaner before the first start in the spring. Mice like to nest in there, too. (Can you blame them?)
When you get back expect the brakes to be grabby at first, since you'll be scrubbing rust off the discs/drums.