Greetings & Welcome!
200k+ miles is a lot for that van… Sounds to me like a case where they’re tired of it being a money pit, so want to dump it on some unsuspecting victim. If it was a good van, it would likely be priced at least double that.
A 1500 is a lightweight van, a 2500 or 3500 would be a better choice. Is it a cargo van, a passenger van, or a conversion van? A cargo van will cost a whole lot more to convert than the other two choices, and make a much inferior, less stealthy, and less comfortable camper. Windows make a world of difference, all positive, and their finished interiors will save you a fortune of both time and money in the conversion process.
If you follow the promoter’s, converting a van can be very very expensive, and not a good idea for someone low on funds. By comparison, my conversion cost under $300 and I have more amenities and more comfort than what the promoters would have you spending $10k+ on.
For most people, a cheap, older motorhome will give you the best bang for your bucks. You can find really nice, move in ready ones for under $2500. I have owned a number of them over the years, and every one of them was an outstanding value for the price paid. A move in ready, running, driving, fully self contained house on wheels in excellent condition, and all of them were under 100k miles when I bought them. Most of them had barely even ever been used, they were just old, but in the case of motorhomes, older also means better built. Built in the days when quality and durability were important.
Good luck & keep us posted.
Cheers!