Cool van, I agree that I would probably look for some outside help in setting a starting price.
I would recommend you make a list of any improvements to the motor AKA "Bulletproofing". I see folks just make a very detailed list somewhere, like here, that can be linked. That way when someone asks the question "is it Bulletproofed" you can save yourself a bunch of typing and just send them the link. So, So many keyboard worriers when they see an add with a 6.0 Powerstroke will get happy feet because they can ask the question "is it Bulletproofed" and they have no intention of buying. Some don't even know what it means but love to ask it as a "gotcha" kind of thing. Hope this might save you some time and good luck with the sale.
2005 SMB RB 4x4 6.0 PSD
A rocket on the pad is safe,
but it's not what rockets are built for.