According to the map below, it looks like parking is in the regular lots, with lots A, AA, B and BB being the closest and likely the most busy -- but who really knows where a shakedown street will pop up (newbs: that's the row or rows of cars where the most action is happening).
More parking information (from DicksSportingGoodsPark.com):
PROHIBITED IN PARKING LOTS: • Animals (except service animals)* • Balloons • Fireworks of any kind • Nitrous Oxide • Unapproved pamphlets, handouts or advertisements • Unlicensed Band Merchandise • Weapons of any kind • All vehicles are subject to search
*A note on the no animals thing: it's hot as Hell out there at Dick's park. Anyone who has been to a past Mile High Music festival can tell you that the dusty parking lots of commerce city in September heat is not a good place for a fur-covered dog to wait it out while you go see a concert. Do your dog a favor and leave him at home in the air conditioning, no matter how heady you think it makes you to drag your pit bull puppy around on a string. Dick's has listed a few nearby animal shelters on their website in case you can't find someone to watch fido.
Camping Dick's park is surrounded on two sides by acres and acres of athletic fields. For past multi-night runs like Mile High Music Festival, they were home to the stages and concert fields. This weekend, the park is allowing fans to camp out on the natural turf fields southeast of the venue itself. You'll have close access, plenty of late-night revelry and the wonderfully bright Colorado sun to wake you up in the morning.
Camping information (from phish.com and dickssportinggoodspark.com) - $70 per person (includes all 3 days and parking) - Each person entering the campgrounds will need a camping pass - Campground is a lush grass soccer field located next to the venue - Opens Friday, September 2nd at Noon - Campground Closes Monday, September 5th at Noon - Tents only - Parking is adjacent to campground in a parking lot designated for campers. - Parking is included in the price of the camping ticket - Cars may come and go from campground parking lot anytime - A limited number of RV spaces are available. Each RV must have an RV pass ($10) and each person in the RV must have a camping ticket to enter RV parking. The RV parking lot is next to general camping. We will have an affordable service provider on site that will be able to refill your water tank and/or pump waste. - Access to Free Showers - Parking for camper's cars will be in Lot R. Lot R can be accessed off of 56th Avenue just east of Valentia. Camping at Dick's is tent-only and cars are parked in a lot adjacent to the campground. You can take your car in/out of the lot anytime you want during the weekend.