Oh my! Oshkosh is the aviator's candy store--too many flavors, too many choices. But there's something for everyone.
One of my favorite things to do in the early morning is sit on the flight line and watch the landings--and the screw ups.
I'm not much into the forums and "how tos", but that interests a lot of people.
The EAA museum is worth half a day. While there, go across the field and take a helicopter ride in a MASH era/style helicopter--expensive for the few minutes you're in the air, but you get to see the whole show from a different perspective. Then tour the old Pioneer Airport hangars--very interesting.
I like to spend some time looking at vendor offerings in the big Hangars A, B, C, & D. Invariably I find something I just can't live without, although the Genuine Egyptian Sheets and the Little Giant Ladders don't interest me. Some of the stuff I've bought, I've never used, but I might someday! Other stuff, I use each time I fly, like my DC One-X headset.
The Seaplane Base is definitely worth going to--free to go, costs $3 to return. It's a laid back respite from the hubbub of OSH.
And there are airplanes--thousands of airplanes.
I do take the trams. With a bad ankle and sciatic nerve problems, walking very far isn't my cup of tea. But it's really not all that bad, depending on the time of day and the weather.
At night, there are the movies at the open-air theater--but make sure you're prepared for mosquitoes.
And take the time to meet people. I've met some really fascinating folks from all over, on the flight line, by their airplanes, at lunch when sharing tables, etc.
But don't try or expect to see everything--it can't be done. I stay the whole week, and every year I go away, realizing that I missed seeing something I'd intended to see. But I always have a great time, seeing old friends, making new ones, doing some of the same things, doing new things.
Oh, and bring money. If you decide to go up in a vintage Ford Tri-motor, or a B-17, or the MASH helicopter, or you see something you want to buy, it all costs money.
And mostly, have fun!
Cary