Trucking is a no set time frame. Meaning one day you'll be driving all day to be on schedule, another day all night to keep on schedule. Sometimes you can get kind of a regular schedule but usually first starting out you'll have irregular hours and loads of stress. That's part of the job and why alot of people who start end up hating it.
Atleast you are looking at the area of trip planning, that's a weakness of most newbies. Usually you can tone down some of the stress and weariness with effective trip planning.
If you want to get prepared, try constantly changing your time schedules. One day go to sleep around 4 am, another time 8pm, and when you get tired try to get busy doing things. This will give you an idea of what it will be like. This is not intended to smart a$$ in anyway, just giving you an idea of what's ahead. BOL