Living in the van full-time is a different budget shape to a holiday trip - build a realistic weekly figure across the categories that actually recur.
Full-timers typically find maintenance and servicing is the category most often forgotten - budgeting a weekly reserve for it (rather than being caught out by one big bill) is what makes a full-time budget sustainable. Figures here are planning estimates based on typical Australian full-time traveller costs and will vary with your region, travel pace and rig. This isn't financial advice - it's a starting point to build your own numbers around.