dafish said...
beware of of the Ford transits. you will sink money into it, very problematic transmissions etc.
Also, avoid any Volswagen transporters with auto, (meaning the price bracket that you can afford year models) they too are VERY problematic and expensive to fix, and will only guarantee them for very low K's. Manuel trans are fine though. I have an older 90 model combi, 480,000 kilometers on it, still no rust, still the original engine with no work done on it ever, and still purrs like a kitten and burns no oil. This has been a dream van.
Toyotas are great and reliable, but like all Japanese vans they rust easy. Mechanically they are great though.
Vans are the best way to travel, hope you find yourself a good one.
+1 on the Kombis. I own a 79 campervan conversion with no significant rust and owned an 81 (same body shape as the 90 model) in the UK. They are cheap to service, have about 3 moving parts and go everywhere (although not necessarily at high speed). If you can get a straight up bus (no conversion) you can pull the seats out and make your own setup. Plus, chick dig Kombis

Rust will always be your problem as vans have a lot of flat surfaces and sills for water to accumulate on. And they tend to have a less cared for life (It's amazing how well you can preserve paint with regular wash and waxes, and vans don't tend to get this kind of loving)
Always go for a manual. For one, they tend to give you more power and better fuel economy. Also you can use the engine to brake down hills, and you don't get that annoying gear hunting effect driving up steeper hills.
Also, for your price bracket, maybe consider a Landcruiser Troopy (early-mid 90s) You can do a lot with the back and from all accounts of friends who own them, they are pretty bullet proof.
Of course, fuel will always a thirsty factor. If you can pick up a van with a gas conversion I would go for it. That said, if you just keep it mainly for weekend trips/highway driving fuel economy becomes less of an issue.