If you want a guaranteed spot. Otherwise there are a few walk up sites if they aren't taken.
No, but it's preferable at peak times.
No, but it's a risk. Some spots are walk up only including some waterfront spots. Depending on the weather and bugs some people may leave earlier than anticipated. We had an inner walk on spot but moved to a lakefront once it opened up. The caretaker couple that was there this year helped us.
If you want a waterfront site then yes during July and august
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