As far as I know, it'll be free like the previous two years have been.
Last year the course was ~85 miles long IIRC. So, once the course info is released (it's held secret till just before the race) you can pick wherever you wish to be, get there EXTRA early, and have some fun.
If you'd like to see multiple race areas, that's possible too within reason.
Be advised, if you wish to be at a place where there's bound to be plenty of action (EG: the plaque on Sledgehammer) you will need to park & hike in. Expect plenty of company to be there as well, plus, pack it in, pack it out.