So I guess that means you are not going to ask your question in the Touring subforum after all.
You could get some valuable insight especially concerns on your route, October temps in the mountains, fewer hours of daylight in the fall.
Riding 160km per day for 20 days is a massive undertaking. One that typically isn’t done with an urgent plea for a “lightweight” touring bike with only a small budget.
Call me skeptical and negative, I don’t really care, but it sure sounds like you are really looking for a free bike.
John