I did this same thing on an '03 E250 extended body with 5.4 gasser. From a quick read of your process LilNuts we took much the same route.
I did have to add a ground wire, run the CTO wire into the cabin and re-configure the cable pulled VSC servo to enable the "cruise control on" instrument cluster lamp.
Assembling a ton of EVTM material created two 24" x 36" print outs in order to re-configure the chassis wiring harness connectors to the F-Series IC--it took me upwards of 6 weeks to accomplish this BUT I wanted/needed a one-time fault less installation as this was my daily driven work truck. I even went so far as to build a mock up install that included harvesting the wiring harness connectors and verifying on a the eventually installed IC I had the right wires in the right places.
The only real "mistake" made was not connecting the proper engine speed wire to the actual tachometer inside the IC. That was easily corrected the same day. Once done all gauges worked, CEL along other warning/alarm IC lamps.
After it was done I was glad to have accomplished it but not sure I'd do it again. I'd kinda/sorta like to have a tach in the IC just not sure I'm up for that task once again!
Glad you got yours sorted out and its still working---those are handy features to have with any engine. Thanks for sharing your process!