I assume by FRN you mean Federal Reserve Note?
Yes. Sorry--I tend to assume that anyone on these forums is One Of Us, and in on the lingo. I use the term deprecatingly, to distinguish them from actual Dollars, which are made of 90% silver.
I will park the car in the over flow lot
...if there's room. Remember, we're expecting a thousand people or more. Last year we had 800-ish, and the "overflow lot" was around half-full. Also, it's clear across the
entire campground from our site.

Make your way to Roger's, and we'll work out the rest once we see the actual situation.
to take up even less space on the site.
It's already paid for; go ahead and use it! My only concerns are 1) physically getting the cars in, 2) getting the gear out, 3) setting up the gear, and 4) footpaths between all of the above. If we can semi-safely maneuver even in the dark, I'm happy. [Note to self: get glowsticks to mark trip-hazards.]
(not sure what that covers besides the car).
Access fee covers permission to enter the camping area, for people plus one car per person/family. Cars without a dated window sticker are subject to Bad Things. (I didn't pay attention to those particular details, because they didn't apply to me.)
Note: if map and memory serve, we have both power (one pair of plugs, 3-prong) and water (one ground faucet, with hose threads). The staff specifically confirmed power when I called in my reservation; I didn't ask about water.