Yeah, that's um.... like 22 miles, so yeah a little long for a commute, on the edge of doable IMHO. I might try that if it wasn't hilly and on a nice day, but everyday... nah. How you vary this is entirely up to you. Some people like routine. Some people like variety. Some people like to cruise and enjoy the views. Some people like to push and go fast. You know best what you like and there are no strict rules to follow other than: (1) Be Safe and (2) Have Fun. So experiment, and do what fits you best.