I may need to transport my wife, who is somewhat incontinent. I don't see how I can enter a public bathroom with her to assist her. I tentatively thought I might fly her out with me to our new destination, once I have completed the physical move, placing her in a nursing home in the interim. But she will need to use the restroom on the plane, and I will have to assist her there. Do airlines make provision for this? If I drive cross-country with her, I will face the public bathroom issue, where my presence will not be tolerated in a lady's bathroom, and her presence will not be acceptable in a men's bathroom.
On the ground, you and your wife can use any facility for people with disabilities, which as far as I am aware are all unisex and have a lot more room for manoeuvre.
As for driving, where I live there are family restrooms pretty much everywhere. These are large single use restrooms for people who need help in the restroom.
Hey! There's a website for that.
findfamilyrestroom.com/
I would consider taking a third person to help assist. Perhaps a female who is trained. I'd also consider the big picture and not just the bathroom issue. Going on this trip could trigger behavior that you are not expecting. With dementia she may be frightened, confused, agitated and even act out in ways that are scary. Especially in closed in spaces with lots of strangers.
I realize that private travel by plane or travel trailer is expensive, but, if funds I allow, I'd explore it. Perhaps, someone around here, who's done it will chime in.
Also, transporting someone with alzheimer's / dementia would be a challenge, I would think.
Someone who knows how the answer this question should find it and I hope for your sake, soon.