Parking will be fine. Aim for the Providence Place Mall garage. It's huge and has signs telling you which levels have open spots and where. You can reserve a space online too. It's also attached via a skybridge to the hotel that's used for panels and shit.

There's other garages. Next biggest is for the convention center and it's half the size. A bunch of others are significantly smaller. Those will fill up quickly

The overselling thing was a huge issue in 2014 when it was still relatively new. Their attendance shot way up and they ended up denying entry/re-entry for most of Saturday afternoon.

I could be wrong, but I don't think that's happened since. Certainly not at the same level as that one year. If you're there by noon, you'll likely be fine.

I think the autographs depend on how popular the autographs you want are. I've seen some ridiculous lines for shit and I've also had a 10 minute conversation with the Honky Tonk Man because I felt bad that nobody else wanted to talk to him. He seemed lonely. A little sad too.