Considering the type of van you have do not expect a well maintained ,smooth, gravel road. It can be pretty rough in spots. Get the best up to date report that you can. You are doing the right thing by asking around.....
The only way to avoid many kms of dirt and gravel will be via Mt Isa and then north via the Stuart Highway or the Tablelands Highway.
Get yourself a HEMA touring atlas and all will be revealed.
Cheers,
Peter
Worked along the road when I was a remote techy. Definitely a 4wd road (Savannah Way). I wouldn't haul a van unless made for off road. Can be extremely rough as well.