Now see what you've started. I've been philosophising for weeks about how to reply to your original post but every time my fingers touch the keyboard I freeze in a crisis of existential angst.

What do I know about bikes or travelling anyway. Is 40yrs enough experience
What if the computer crashes and everything is lost?
What will they think about my spelling / grammar?
Do I have the right to interfere in another person's decision making?
Will they take my post in the right spirit or will I be abused, insulted and belittled?
Does it really matter, have I not got anything better to do?

Well, for what it's worth (and for as long as the tablets calm me down) here's my 2C worth (or whatever the equivalent is in UK money):

Firstly - stop reading other people's ride reports / stories. They are all (even the ones I've done) works of fantasy, being at best a third generation (and usually Romanticised) copy of what actually happened. They bear about as much relationship to travel reality as a rom-com film does to falling in love with your wife.

Secondly - understand that whatever you do it will be wrong. Planning a trip - any pleasure trip, but bike travel has unique planning issues, involves trying to predict the future. Some things you can probably guess at - how many miles till this tyre (I'm in the UK so I spell funny) wears out etc but most things can't. You'll take stuff you don't need and forget stuff you do. I've lost track of how many bike trips I've done and I still mess up entry level stuff.

Thirdly - believe in yourself. Your spirit is far far more important than your planning list. Unless something life threateningly serious happens triumph and disaster are the same thing - although I admit you might not think that when you're stuck at the side of the road overnight. If you actually enjoy riding a bike you'll know in your heart of hearts that many of the items on your worry list are really non issues. I think I took a list of Honda dealers in Europe with me on a trip I did in 1971 but I've not bothered since.

Fourthly - get a grip on the age thing. I'm the same age as you so I know what works and what doesn't. A friend of mine (also 63) who lives in N.J. had to go down to Baltimore a couple of weeks ago for some medical investigations and (out of choice) rode down on his Triumph and camped overnight in a rainstorm before going to the hospital. Via a few sightseeing detours that turned into a 1000 mile trip. There was no staring into the fire embers at home beforehand and worrying about running out of fuel or punctures. He had to go to Baltimore so he got on the bike. A couple of years ago he rode the same Triumph out to the west coast to visit a list of business customers rather than fly /drive.

Lastly - recognise your list of issues for what they mostly are - anxiety. Rather than looking for a bunker to hide in when you throw the hand grenade, wonder instead what it looks like when it blows up. The whole point of this is to see what's out there.