I have the exact same problem, I have a bike with 44.5" height, and when it dies the replacement [a different brand] will also be 44.5".
Let's assume that I'd like to have around 46" clearance to be conservative and give me room to get my hands and straps in there, too.
Here are my issues in order of importance.
Issue #1
The side or rear door wagon clearance is 44-45". Can that be increased by removing trim?
Van side door is 48" so I assume so?
For rear door I assume no.
If the door isn't tall enough, this whole thing is moot.
[44.5" bike height is after removing mirrors and windshield. There's nothing I can practically do there other than deflate the tires I guess. ]
Issue #2
I'd like to keep the original floors if possible, I'll remove the seats and the rails, but otherwise keep it factory-ish.
This means all I have to do is remove the ceiling trim. I'm not concerned about resale, just my time and effort. Also a little bit concerned about road noise if I mess with the floor. Can I get the height I need just from removing the [rear] ceiling trim? That's going from 42.1" to 46", so I'm asking for 3.9" from the ceiling.
Or is that unworkable and it all has to be done with the floor?
Or with floor AND ceiling both?
Issue #3
I'd like to be able to sleep in the van on a bedroll. Therefore, I'd prefer that my bike fit to one side of the wagon and not have to be in the middle. Is all the height in the middle or is it uniform from left to right?
(I don't need the height at the very edge of the van just maybe a foot from the edge.)