If you're planning on riding 5 consecutive 60 mile days, you really ought to be doing enough riding on the bike you're planning on using to know which gear setup you will be comfortable running. Ride your bike, find what works. Planning a 300 mile trip on a bike you're not already familiar with on moderate distance riding is a very bad idea.
EDIT: Saw that this post was older than **** only after posting this, disregard