Unlike buying a car or other common vehicle, there's a good chance you'll need to travel a significant distance to make a good purchase, especially if you're seeking a very niche vehicle. You might be limited to vehicles near you if you can't afford to make potentially multiple trips to see far-away vehicles, but the expense of travel could more than pay for itself if you find a good deal on exactly the vehicle you need.
Florida and Arizona has been touted as a place to find commercial campers and RVs. Retirees from the NE plan to RV together in that warm state but either change their mind, upgrade to another RV, or stop RVing because of health or age reasons. There is no ice in Florida (hence no road salt) but do look for rust caused by salt water breezes or drives on the beach.
The American Southwest is another good place as there is no road salt. Paint can be degraded by “sun fade”1) but that is cosmetic rather than functional. Tires can be dry rotted and dashboards and interiors sun-damaged.2)
Colorado does not use road salt, relying on gravel instead. Locals advise that cracked windshields from gravel are to be expected.3) 4×4 campers may be more common in mountainous areas.
Vehicles that have not been on the beach in California will be in good condition but may be more expensive4) due to higher cost of living.
Once you know geographically where to look the search comes next.
Take advantage of any automation tools the site offers (email alerts, saved searches, RSS feeds).5)
If you can buy something that already has part of what you want, even better.
Former Ambulances can make good starters for a built, due to pre-existing high-tops, beefy electrical systems and cabinets. However they often have a lot of hours of idling on them, and many are diesel which are problematic.
Wheelchair Vans can be great to start with. Many will have fiberglass high roofs added, or larger doors. If you can find one that still has the hydraulic ramp in it, many mobility conversion companies will remove them for free and might even pay you a few hundred dollars for them.
Passenger vans can be better than cargo vans, especially the extended E-Series or Transits that were sold from the factory in a full passenger configuration. They're used frequently for airport shuttles or fleet transportation usage, which often means mostly highway miles which are less impactful than stop-and-go city driving that can be seen by delivery vans. Because they're mostly transporting people, you don't have to worry (as much) about damage or contamination from possibly toxic chemicals, paints or other substances that tradesman might commonly transport.
The former church or nursing home transportation van is the golden ticket if you can find them for sale.
Some vans will be a “hard no”, as in “walk away”. Others may need to be heavily discounted to account for required maintenance, condition, or branded title.6)
Also see: Don't buy a lemon (yt Bob Wells)
Untitled vehicles can be nightmares. Here are some questions to ask to avoid this issue:
Rule out vans from any seller that will not allow the van to be inspected by a mechanic. This is called a “pre-sale inspection” (PSI) or similar, and typically costs $0 - $150. Many/most expensive horror stories could be avoided with a PSI.
The VIN must match the title.
The free Vehicle History VIN check will show a surprising amount of info from various public sources.
The free NCIB VIN check will identify salvaged (totaled) and stolen vehicles.
The free Carfax Flood VIN check will identify flooded vehicles.
Consumers CANNOT receive NMVTIS Vehicle History Reports from Carfax, CVR, DMVDesk, Experian, or TitleTech; these five entities provide information only to car dealerships.7)
If your vehicle passes all those you might want to look at the free NHTSA recall VIN check to see if there are any outstanding safety recalls.
In addition to the VIN check above, pay attention to mold/mildew smells. Lift trunk carpet and look for dried mud.
Structural rust can cause the vehicle to be uninspectable, unsafe, and possibly unrepairable unless one is willing to apply heroic levels of money and skill.
Some states in the northeast and northern midwest use salt on the roads to melt ice.
Colorado and Utah use non-salt chemicals or gravel on the road.
Alaska is often too cold for road salt to be used there, so salt use may vary by area.
Don't be tempted by that super-cheap van you found that “needs a little TLC”. If the need was little, the seller would have done it already and been able to sell it for a higher price. Unless you really know what you're doing, avoid buying a fixer-upper as your first van. And I'll be honest; if you're reading this wiki, you probably don't know what you're doing (yet).
“No van ever cost less than $5,000”
Don’t start too cheap. Buying beaters or fixer-upper projects is great for people who have a lot of mechanical skills, DIY abilities, and already own a lot of their own tools and have a place to work on it. But if you think you’re going to get an old beater and then pay somebody else to make the repairs, you’re going to end up spending far more money than it would have cost to just buy a more reliable van in the first place.
Spend more on the van, spend less on the build out. Spend more of your budget to get a solid and reliable van, and reduce your budget for the interior amenities; you will enjoy a reliable van with a bare-bones interior much more than a fancy interior that is broken down on the side of the road.