Most people pack w-a-y too much for their first tour!
Lots of stuff can be eliminated, and 'if' you need something, buy it on the road.
Carry usual bike kit, Morph pump, couple tubes and folding tire. Do you really need a Garmin? Hell, have traveled all over US/world without one. Cell phone? Great in emergency, but don't own one . . . who you gonna call . . . AAA?
Don't pack a razor (grow a beard); have gotten along fine with plain old water (you'll drink more of it out west!) and use sunscreen even at altitiude on cloudy day.
A garbage bag makes a fine raincoat (cut hole for both arms/head). If its too cold out, wear your warmest clothes and that garbage bag/raincoat and crawl into sleeping bag!
Sounds like you've got enough miles/experience under the tires . . .
It's and adventure; improvise as needed . . . and enjoy!
Pedal on!
Rudy and Kay/zonatandem