Yes, you can absolutely spend the first night in the RV and go through the orientation the next morning. It's a very common thing to do because a lot of planes arrive in Anchorage after the office closes. Everything is clearly explained as you go through the booking process online.
Yes you can
If you are doing the Spring Adventure Package, you must be there for the orientation. I do not believe there are any exceptions. It takes several hours. You do spend the night in your RV if you have made previous arrangements with GAH. There is not a fee for that night.
No, you can't do that
You'd likely be charged from the moment of occupation. But I'm sure the contracts etc. Would have to be done first to protect them and you from things that can happen.
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