You can set up on Friday and no one will bother your tent or tables and chairs if you leave them there. At least in my experience that kind of stuff is pretty safe. Of course use some common sense and don't leave anything valuable. There is room on Saturday and it usually depends on what game you're coming to as to whether you get good space or just space. No one manages the Quad from the standpoint of space other than the areas reserved for tent rentals that come from the University. So you just show up and squat and play friendly. Check out the Quad Map for when you can drop off because if you have a bunch of stuff you don't want to be hauling it from the soccer fields parking lot.
Quad Map
If you're coming for Penn State or an SEC game the competition for good spots get's more difficult and Friday would be preferable. If you're coming for another non-conference foe, like Georgia State or San Jose State, those will be night games and I wouldn't bother coming until Saturday morning.
I've tailgated on the Quad and there is nothing like it, but it is very crowded and busy. If you've got small kids you'll have to keep an eye on them to make sure they don't wander off in the crowd.
Good luck.