I'm booked for a stay in mid-August, along with a week on other islands with a MR island-hopper award (thanks again, Caroline!!). There was also a similar thread to get your name on an invite to Princeville on Kauai that I just received on email about. Maybe that will be next summer....
From our discussions with the folks on the property, no timeshare/vacation ownership sales pitch is involved, other than the "we want you to experience it - we think it sells itself". I have heard that once you are there, you can choose to attend a seminar for an additional offer of $$/points, but it's not required as part of the package.
I haven't called Avis yet, but since I found a rate for a full-size car for $161 all-in, I'm hoping the $185 will cover the car for all 5 days.