Good for us newbies that are going next year!
My experience last year:
OSH was flooded early in the week, so camping was very limited. Things did open up later int he week.
My buddy and I were hoping we'd be able to get in, but had already planned to stay at FLD. OSH was our alternate, and it all worked out.
Read, and follow, all NOTAMs. Both for OSH and whatever your alternate is. Don't be that guy that calls FLD tower (when the NOTAM says something like, 'don't call tower until you are 4 miles...', or whatever it said) and say "xxx is on a 24.7 mile left downwind for runway 36". Yes, that really happened, and no, it wasn't me.
The FLD tower and ground controllers were outstanding. I only had to talk with them a couple times, but I did have to listen to them handle other traffic. They were great.
FLD experience itself:
Airport: It's a nice airport, they had lots of parking for both parking and camping. Two rwys, but they closed the crosswind rwy and used it for parking. Camping was on the grass. The FBO was open for breakfast (coffee, donuts, breakfast biscuits) at a reasonable price, but it does add up over several days. They do have bagged ice for your coolers, but I had a problem with that. By the time we got back from OSH on the shuttle bus each night, the FBO gang was gone for the day and the only ramper that was there didn't know anything about selling ice. So get what you need during normal office hours, which means first thing in the morning.
Fuel: They gave us a fuel hang tag for the prop. Put that out as soon as you can. Even doing that, though, you might end up finding yourself ready to leave and the fuel truck still hasn't come by. We were there 3 days (2 nights), and we still had to wait several hours for fuel on our departure day. There is a self serve island, but the wait in that line didn't seem to be much better. Get fuel as soon as you can. If your fuel tank can only be accessed from one spot, don't put your tent there.
Camping: Bring some sort of shower shoes - sandals, beach shoes, water shoes, flip flops, something. The floors of the shower trailers get pretty sloppy with water, dirt, and grass clippings. If you have a high wing you will be tempted to put your tent close to the trailing edge of the wing. The problem there is that dew will drip off that wing and onto your tent all night. The camping area is very close to the highway and traffic noise that first night will mean you will have trouble sleeping. Following nights won't be as bad because you'll be more used to it. If you can get acclimated to sleeping with earplugs before your trip, that might help. And bring the most powerful insect repellent you can find, the mosquitoes are vicious.
Transportation: There are shuttle buses that run between FLD and OSH. You can buy one-way or round-trip tickets. Something to consider - they do have a "last pickup" time, and that time last year was before the end of the Wed night fireworks show. If you want to stay for the whole show, you really will need to talk with the bus service and ask if they have a late pickup that night. Otherwise you'll either miss the last bit of the show or will have to make other travel arrangements.
I'm sure there are a few things I forgot, but half the fun is figuring this stuff out as it happens.