I'm working for my college newspaper and they've procured me a credential to shoot on the sidelines of a D-I game in two weeks...never done this before.
I hope some more experienced folks will chip in. My only experience is one amateur game, so take this advice with that in mind.
I've got a 5D3, 16-35 II, 70-200 II, and a nifty 50, as well as a 430EX. I also have a 500L II and a second 5D3 coming via the CPS Loan program that I plan to use at this game.
Drop the 50. 500 is probably too long for most of what you're doing. 300 or 400 would be better for tight shots.
You'll use the 70-200 when the action is near you, and the long lens when it's near the opposite endzone. The 16-35 could be useful for reaction shots: up close after a TD, interception or the like (though obviously, don't get in the way)
Flash of any use?
Probably not. D-I should be well-lighted.
Obviously I want to keep my team facing me, but how is movement governed on sidelines. Can I get up and go where and when needed or am I locked down?
Call the press office of the hosting school and explain your situation. Ask them for guidelines on etiquette and movement. I've seen some D-I where the student photographers can move quite a bit. When you get on the field, ask advice from some of the other photographers.
Shoot bursts for all action. Try to anticipate the play. Remember that there are some shots you can't get because they're obscured, so it's better to follow players (wide receivers) who may not get the ball every play. On the other hand, if it's a likely running play, look to burst on the RB coming through the line. If the line stops him you're not getting the shot anyhow. Also think about covering an area: if you know it's third and 12, look for action from 10-15 yards from the line of scrimmage. Take some risks: better to get a few glorious shots than pedestrian coverage of every play. Bring ENOUGH BIG MEMORY CARDS. You will shoot several thousand frames during that game.
One more thing I tried to do toward the end of my one game: keep both eyes open during the play. Your "off" eye should be looking over the camera for the action, while your viewfinder eye is ready to focus in. Keep the camera at your eye for the entire play: don't expect to bring it up in time for action.