I've had 2 S700's in the last 15 years and I love them. Assuming you are not afraid of a toolbox and rolling your sleeves up, then this is my advice. You won't find a perfect van, so it's a matter of how much money and work you are willing to commit to any given van. Most things in a van are cosmetic and not worth getting worried about, as long as the price isn't daft. Batteries, appliances, fridges, wiring, front dash board etc are all reasonably straightforward DIY jobs, and there is usually plenty of work to be done, unless it's been kept on top of by a previous owner. So what you are really looking for is a van that just "feels right" - something that can be worked on - a vision. At a basic level it is a box on wheels, so it's the box and the wheels that need to be looked at most carefully. Look at the expensive things. You want an engine that sounds quite sweet and isn't leaking oil, although some oil leaks can be easily fixed. A bit of smoke from cold is fine and should fade away. Check an auto box very closely, it is imperative to have a test drive. The van should move smoothly through the gears, and kick down on hills. You want progressive acceleration up to 50-60 and then a reasonably smooth cruise - these vans are not fast. Manual boxes should select all gears normally, but don't worry about 1st gear being stiff and difficult to engage. It's a crawler gear and designed to be selected at standstill. If the stick feels spongy and sloppy then it's usually the selector mechanism, not the box itself, and easily fixed. I have written another article about this on this blog. Steering should be reasonably tight and vibration free, but problems here are usually just a matter of worn bushes and easily fixed.
Next, use your nose and smell for damp. Old Hymers are generally watertight unless they have been damaged or abused.
Around the front end drivers door, if it has one, and the dash board - which is a favourite for getting rotten - it's a piece of plywood and gets soft from all the condensation that drips down the inside of the windscreen. It's a weekends work, and pretty much every old Hymer needs it done at some stage. A knowledgeable seller will tell you if it's been done, but if not, rock the van from side to side, inside, and if you see any movement between the bottom of the windscreen and the dash board, then you know it will need doing. It shouldn't be a deal beaker if you like the rest of the van and are handy with tools, a drill and a jigsaw.
Then take a good long look underneath - you are looking for any areas of bad rust on the main chassis members. Hymers were very well undersealed at the factory, so don't be suspicious if you find it surprisingly clean, but occasionally you will find chassis members flaking with rust, especially behind the back wheels. If the van has mudflaps at the back wheels, that's a good sign. Also check the rear of the floor right at the back in the boot - it gets rotten with all the road water.
Also - these vans have character. Just sit in it quietly for 5 minutes and imagine yourself living in it. Hopefully it will whisper to you!
Price wise - The Germans are asking around £16k for fully loaded lovingly maintained examples. For this sort of money it should be perfect. More than perfect! Most UK vans that need a bit of TLC are around £10 to 13k. Maybe a bit more at this time of year. The right price should be the purchase price plus whatever you need to spend to get it up to scratch, so if you have a fixed budget bear this in mind. If you find any areas of concern and need advice, take pictures and an audio recording of the engine and come back on here. Good luck!

