I think, for a 10 AM practice, the line for checking in will start to build at around 8 AM or so. It might be even earlier because of the great post season. I think the check-in opens about an hour later (9 AM), you get your wristbands, and the buses start rolling.
When you arrive, look for where the main camera towers are located. That is where the bulk of the scrimmages will take place. Various squads will practice all over the place, but generally on the same field designated for scrimmages.
If you are there on a day when the main practice is on the field right in front of the berm, then you are in luck. There is a lot of seating and I think the middle of the berm gives a great view. Lots of people like to hang on the fence and so it gets a little crowded.
Chairs and a cooler aren't any problem. Make sure they are the low slung beach kind or get there early enough so that you are not setting up all of your stuff in front of someone who might not see past you - common courtesy.
Lots of autograph seekers hang on the fence near the VMAC building itself but I've heard that the past two years have not been kind to folks looking to meet and greet players. Most scoot on in to the facility, visit the VIP area or just sign stuff for kids. It will be a madhouse this year, I suspect. The best time to get Wilson's autograph, for instance, was when he was comPETE-ing for the starting spot. Once he hit the big time, it became kids only, if that.
Other advice - arrive really early and leave when the horn for the last rotation sounds. You'll see almost everything and won't have to stand in line for a return bus. Bring lots of water, sunscreen and a hat, even to morning practices.