What does the van actually cost you in a year, not counting fuel and food on trips? Depreciation, insurance, rego, storage and the servicing/repairs you'll inevitably need - the numbers most people underestimate before buying.
Depreciation is estimated using typical Australian caravan depreciation bands: around 15% in the first year, easing to roughly 8%/year through years 2-5, and settling to around 5%/year from year 6 onward - similar in shape to car depreciation curves reported by Australian insurers and dealers, though your specific van, brand and condition will vary. This is a planning estimate, not a valuation or financial advice - for an actual resale figure, get a dealer appraisal.