A recent poster on MSN Caravaners Forum asked for tips on buying a new caravan, and asked what others considered to be "must haves".
I've pasted some of the comments below for future reference for when we decide to upgrade our caravan.
This will depend on your travel plans and how many people you need to house… for instance the sort of van one might buy for trips of 2 or 3 weeks and weekends here and there will be markedly different to a van you would need for long term touring.
Think about whether you want a shower/toilet or not. There are those who hate them, and those who love them. I'm in the latter group because I like the convenience and comfort, and don't like traipsing across the park to the toilet block especially on cold, wet, windy days (and nights). But they do take up a lot of room in a medium sized van, which could be useful for additional storage.
Storage is both a boon and a problem. All vans have specific weight limits and too much storage space can cause problems if it's used enthusiatically. Again, there are those who like minimalist travelling, and those who want to have each and every comfort of home with them. I think I'm somewhere in between, and trying to get more minimalist each trip.
Unless you have storage problems, full height is recommended. If you don't want to use up too much interior space with shower etc., get a built in slide out toilet, and fit an outside shower on wall of van. Takes up no room. Have a curtain, fitted tent to suit. I like separate ends, with privacy at one end, for sleeping and reading/TV, and living/kitchen at the other end with divider.
Buying a second-hand van, make sure you check for signs of leaks. Look behind the curtains to see if there are any tell-tale stains around the window. Lift the seat cushions, and look under the seats. Also check under the bed. It's too easy to look around the van and think everything looks very nice and clean and well looked after, but make sure you check the hidden places, too.
Have a good look underneath ANY van, new or old. With second hand you are looking for stone damage, rust in chassis, or rot in floor. Look at the tires for uneven wear that may indicate axle misalignment. Ensure it has relevant gas and electrical certification. If it has a battery ensure it is in a vented enclosure. In my mind the dual axle V single axle is not clear cut. Advantage of dual axle is usually better ride and higher carrying capacity. Disadvantage is hard to manouver by hand and strain on components whilst turning sharply on hard surfaces (I always shudder when I have to do this with tandem trailers). Many people think that tandems are better in blow out situations. Not necessarily so. I have had a blow out on a single axle van whilst passing a slower vehicle, so I had the boot into it (wont say how fast, but it was in N.T.). I only knew something was wrong because I heard the bang and a viabration through the car, no sway or dramas at all. In a dual axle van if a tire on the rear axle blows (and it usually is) it could alter the ball load which could induce instability. I have had this happen on a dual axle trailer (non load sharing) and it did get quite unstable.