buying an old campervan - is this a good idea?

I have put this on another thread but wondered if putting this under a new heading i might get a response.

We are in a dilemma of if we should sell our beloved caravan to get a camper van but realise we would miss it for our summer holidays when we tend to want to base ourselves at a couple of sites and drive around the little villages (not great with campervans) we have just seen a really old 1989 fiat ducato autosleeper 4 berth advertised. 1.971 petrol engine (i know diesel is much better). it says it was done up for a motor home project in 2007 and that it has service history etc and is £4500. It does have 80,000 miles but a service history. something like this would be good for us as we could keep our caravan for our main holidays but replace our falling apart old 2nd car with this and have a weekend small size camper van? still alot of money for something so old. does anyone have old camper vans around this age? obviously damp and engine would need checking but wondering if it is stupid to consider doing this? our son has aspergers so having something to go away in that is a "safe" space is really good, but not if it falls apart after a couple of years. thanks