The truck has a frame like a thick gauge "c channel", does it not?
The van frame is more like sheet metal square tubing.
I don't see an easy way to make it work.
Of course anything is possible with enough thought and skill.
Looking forward to seeing what you come up with.
Good luck and keep us posted.
I am a retired welder (as of 10-2018) by trade and a lot of what I did was repair frame rust, body, and suspension mounting points. I have to admit the last big Dodge van I was under was a 2002 (or a 2003) model year. I assure you that van had a front subframe very similar to the front frames on the 60s and 70s C body cars. The front frames bolt onto the unibody just behind the trans crossmember and are built from 1/8" steel.
The van chassis used for most motor homes were probably from the 1970s through maybe the 1990s. Those have heavy gauge boxed steel front frames. Gene
