What did you win? Sometime K&M gives away memberships, sometimes it's just gifts.
Many (like 20+) we won a membership, with rights to all future parks, at the time they owned two parks, today its....eight (?).
I'm going to guess that K&M is giving you a basic membership to one park, with no rights to any of the campground exchanges (Coast to Coast, ROD, etc).
They would want some money from you to get rights to the other parks.
Now, if they are giving you a choice in which park, the park at Blaine should be quite close to you and you may find it suits you, it is, quite a nice facility.
It might be, that what they are offering you is something you will use, it might not, you need to talk some more with them.
They are a reputable membership campground company. They are in business to make a profit, but they are still in business after 20+ years, and still buying campgrounds and expanding.