Carringb, so I was wondering (I've never been to junk yard),, but do you think it would be posssible to find a salvaged E250 2011 -2014 and try to get the tow package wiring harness off? I'm talking about the part from the dash to the rear of the van. I agree like you said most if not all these vans have the dash wiring and connectors for the tow package.
I too would like to use the Ford OEM Brake module and I can still find that online. Its pricey but you can find it. I could get someone to install a new brake master cylinder if that had to be done.
I wish I could see one ( the wiring harness, pigtail etc) factory oem installed on a van. I've never even seen that. I hate to go up to total strangers and ask then if I can crawl under their van,,, but I may have to do it.