GCGDN3 is called Bo's island. The island is not!
Swan Island is a bit further by boat because they do not allow landing at the same place as the ferry. You need to paddle to the other side of the island.
Little Chebeague also has camping, but I think it has less capacity. It doesn't look like we have too many people as of now, so that may be a good option.
I personally love the idea of going to Jewel. I haven't been there and it's a good way to get those missing caches!
It just isn't a good place for inexperienced kayakers unless conditions are perfect. At the very minimum, everyone who goes out there should be able to perform some type of self rescue, like a paddle float rescue.
A chase boat would really add to safety.
One more thing about Jewel, if you are expecting a quiet, personal island experience, you will be disappointed. Everyone who I've talked to says that it is a bit like going to the circus. I love the circus!