Plenty of people have successfully converted vans and small busses into campervans. The reason some are more successful than others is often down to the previous life the vehicle has lived and what sort of preventative maintenance it has been treated to.

A vehicle that has been serviced properly and used carefully is likely to be a good thing even with a few years and plenty of kilometres on board. But one that has been used and abused and neglected in terms of maintenance is not a vehicle you want to be buying second-hand, regardless of make or model.

So make sure the vehicle has a complete service history and try to find out a bit about what it was used for. Does it have a big tow-bar fitted? If so, it's probably towed some heavy loads and that places stresses on every part of the vehicle. Is there any sign-writing on the vehicle (or shadows on the paint where corporate logos once were)? If so, the vehicle has almost certainly been used commercially and may or may not have been driven sympathetically by the company apprentice.

Treat it like an archaeology project, and you'll be amazed what you can learn. Meantime, a privately owned Express van with full service history is the one you want, but be prepared to pay more for such a thing.