[surly Bill]

Just saw your second message. I don't really remember if any other dash parts need to come off, I recall just popping it free and lifting it out. The pics look like there's that one big tab at the bottom that needs to get pushed in by a screwdriver or something. Maybe you're right, and you have to go at it through the cupholder. I think THAT just has a single screw hidden under the rubber pad on the bottom.

 

[surly Bill]

That panel on top of the dash right in front of the steering wheel pops off with a trim tool. In Europeland, that is actually a cubby, with 12vdc power! (like the 2020 Transits have)

With that off you can get pretty close to the middle of the dash. I fed wires through to the Metra doubleDIN stereo adapter through that. A lot of blind poking to get around the hvac vent, but it can be done.