I really like the layout with the 4 captains chairs. You can always build something for about the same price as what these are selling for now, but you also have to deal with all the down time it takes to get it done. If you want to enjoy the rig now, then buying something that's already done might be worth it. But ultimately, you have to ask yourself if the layout is what you want. You can always add 4x4, but changing the layout would require a lot of work.
I think if you can get the van for $60k, you would be doing ok. You said they were pretty firm at $65k, but they've been trying to sell that rig for a while now. People will always prefer the 7.3 over the 6.0 so if you have to sell it down the road, that will always be a selling point. If the rig is as clean as it looks in the pictures, I don't think you would lose much if you ended up having to sell it down the road.
2005 E350 Chateau - V10 - Agile Offroad 4x4
2012 CTS-V Wagon - For the baby...