I know there are regulars here who live in the Phoenix area, they may chime in. But I've gone a few times, and here's my 2 cents. I have never had an issue getting tickets at the gate the day of the game, even right before the game. Also, it is a small park so pretty easy to move around and sit where you want as the game goes on. Very casual atmosphere. However, if you want certain seating (right behind the Brewers dugout for example) that would probably require you to order tickets ASAP, if it's not too late already. Also, keep the sun in mind. If you rather sit in the shade, make sure you mention that when buying tickets. We sit in the sun, and just move to a shaded area if it gets too hot. We always visit a couple other parks during our trip. Gives us a chance to see other areas of Phoenix. It's also fun to scout out restaurants, sports bars, brew pubs, etc. in these different areas. As Nate mentioned, we usually drive up to Sedona for the day. Last time we rented ATVs, and that was a blast! There are trails to hike in the Phoenix area, as easy or difficult as you want. Or you can just drive to the top of one of the mountains for a great view. I'm not an autograph hound, so can't help you there. But I always see people hanging on the rails next to the Brewers dugout. Some players sign, some don't. I'm sure that varies by day and time on who signs, who doesn't. My gut tells me the earlier you get there, the better. Have fun!