I've hunted exclusively public land for the last 2 years. Prior to that I had a stink of 3 years where I hunted only private on my in-laws farm. Before that (10 years or so) I hunted only public land. I've taken alot of animals on public so I can give you a little advice.
1) Like mentioned, most guys will be within 1/2 mile of where they parked.
2) Most guys will only hunt til 930 AM and come back for a 3 hour hunt before dark.
3) Have a plan on how to get your game out, if you do harvest way back in the woods
4) Bring snacks, water, and pack light
With the above two, you can sort of plan out a hunt. The guys walking in for their afternoon hunt will push their deer in towards you, same when they leave in the morning, so sitting all day or mid day can be very productive.
Do a lot of internet (google earth/aerial image) scouting. Try to stay off the field edges that are visible from the road. Find funnels and other pinch points where the deer will be throughout the day.
Hunt during the week if you can, of course less pressure.
That all said, there can be great hunting on public land. If you do get it done, you'll have a great sense of pride in your harvest.
Good luck. The journey has just begun.