I disagree.
Vans are basically camp site and hook up ready and don’t need refillable lpg or
solar panels if this is 100% of what you do. Security is still worthwhile as daytime you may be parked up somewhere.
If you already know this will be a minority use and wildcamping is the main use then the above upgrades (refillable LPG, a
solar panel, and security) are a bare minimum before even first use (in my view anyway).
The only question mark might be that after a few weeks you find the van you purchase is unsuitable for your needs and you need to exchange for another. But how often does this occur?
Normally buyers have done the research, narrowed the field down to 2 or 3 models and a single layout, worked out what they require before purchasing, and then going for the best deal available.
An option before doing anything of course is to park up the van on campsites and get used to van life and how it all works before making upgrade plans. This may be the most sensible course of action.
We already knew what we wanted being former caravan owners so for us immediate upgrading LPG,
solar and security was essential even before first use.