Long post, but you asked for it...
*** If you haven't done it before go to the Hawk Walk. Usually 2 hours before kick. It's at the plaza on the south end of the stadium. The players, staff, and coaches will show up in a bus from their hotel and you can line up and watch everyone walk in with Back In Black playing over the PA. Players and coaches all file through and touch the Kinnick statue as they walk in. The only time you're ever going to get 18 inches away from Kirk Ferentz if you don't live around here.
***Get your picture taken with your boys in front of the Kinnick statue. It's required for those who haven't done it before. There will be plenty of people willing to take your phone and snap a picture of you and your group. I've done it for others countless times.
***90 minutes before kick there's also a marching band performance at the indoor track facility which is immediately next to Kinnick. Free of charge. The HMB performs their halftime show in it's entirety as a dry run complete with narration, it's cool. My niece is a freshman in the band this year and 2 weeks ago was the first time I went. Very worth it IMO.
@HuckFinn goes to this as well, I believe.
***For food my impartial favorite is Wig and Pen pizza. Main drag HWY 6. Lots of great places to eat, just have to search around because everyone has their preferences. Food stands outside the stadium are pretty much just county fair food. Over priced and not real special. Funnel cakes and pork tenderloins...shit like that.
***We tailgate and will be at the game. Ours is in the Myrtle area which is about a 10 minute walk to the stadium if you walk slow. For new people who don't have a spot to go already I
ALWAYS recommend the Mennonite Church lot. $35, close to the stadium, great crowd and it isn't hordes of boozed sweaty 19 year-olds doing Jager bombs with super loud raver music and vibes. Very easy in and out. Unless hordes of drunk 19 year-olds are your thing...for that you want either Melrose Court or in front of any of the dorms/frat houses.
If you want
free parking with tailgating park in the Hancher lot. No charge but it's first come first serve, and it's about a mile walk to the stadium so keep that in mind. Still a great place to tailgate if you and your crew are fit enough to get a walk in. They also do have a shuttle but depending on when you get there it can be a wait.
@HuckFinn parks in Hancher and takes the shuttle every home game. Some people like Finkbine tailgating, but it's the same walk as Hancher and it costs money. It's pretty blah in my opinion.
You can also do private tailgate spots in residential yards all over town but I HIGHLY discourage it. You can never trust that you won't get your car hemmed in with some other jackwad blocking you in, and residential parking is an absolute nightmare to get in/out of.
***Go in the stadium as early as possible. If you've been gone that long seeing Kinnick for the first time will give you butterflies in your stomach. You'll get to see warm-ups on the field with really loud music and it'll get you pumped up. Take it all in and relish in it. I remember my first time walking in when I was a young shaver, and I remember my kid's eyes the first time he walked in. Those of us who've been to a million games get a little jaded so don't let anyone tell you it's no big deal. Open your eyes and ears and take the experience in. Purdue should be a win so it'll be a great time.
***Don't leave early. When we win the Hawks will run back to the tunnel and the HMB will play In Heaven There Is No Beer. If you're coming all this way you need to see it.
***If it's your first trip, have one of your crew video the Wave on their phone. It's the best tradition in all of sports (college or pro) and that way you have proof you did it once.
***Do not buy food or beer in the stadium. Eat/drink before or after the game, or both.
***Do not be in a rush to get to your hotel after the game. I've been to lots of college football venues around the country and Iowa City is pretty much the worst one as far as egress. If you park in Hancher it's a little quicker out but not much. I'm in the Myrtle area and we always plan on sitting for at least an hour minimum before we even try to get moving, longer if it's a big sold out game. IC traffic is total lockdown both in town and on 218/380 right after games. You can either sit at the tailgate for an hour in a comfy bag chair, or you can sit in traffic not moving for an hour idling your car, wasting gas, and being pissed off. Choice is yours.
EDIT: Just read in your post that you were here in 2010. So maybe it will only be 87% as cool for you walking in but your boys if they haven't been before will be impressed. I do know the experience is a lot better in terms of video boards, music, intros, and the stadium has been remodeled and improved a lot. It's WAAAAY louder now with the north endzone redone.
If you have other questions hit me up.