Oshkosh questions

I'm thinking of making my first trip to Oshkosh this year.

How far in advance do I have to plan this? For example, how quickly do
the local hotels fill up? (Haven't made up my mind if I will camp or do
the hotel thing.)

Do I need a reservation to park the airplane? If so, how quickly do
they fill up?

Not being someone who needs to see everything, how many days should I
plan on to get the true experience?

I'm sure I'll have more questions to follow, so please bear with me and
thank you for your useful inputs.