I was about to say it’s a fuel injected motor looking at the AFM. If it idles poorly check the vacuum hoses and any other pipes / joins in the system. Replace perished ones as they cause issues
You often find interiors being sold on eBay. I got a spare Dormobile interior that way. If they’re no good themselves you could use as a template to make your own.
The van isn’t the tidiest paintwork, nor is mine, but that won’t stop you using it. Try and think what you may use it for, especially with young kids. I’ve not got children so am happy with using mine with just a bed in and an awning with a stove and fridge in if away a few days. Tho I do super miss being able to make a cuppa inside the van, and having heating when it’s cold but then again I’ve only ever had two vans with diesel heating and rarely used it! Is that a bed you have in already? I think you can get a hammock that goes across the front of the van for small children? What would you need to get you started? A hob? A fridge? Do you have electric hook up? Just a few thoughts.