I've camped the South Arm remote sites probably a dozen or more times. It's my favorite trip of the year. Our favorite site on the lake is Bur 1. It's got a cove with deep water, you can leave your motor down and it's a real sandy beach. We like it because if it's blowing you can still load the boat and depart camp easy. It's by far the most booked remote site they have. This is it, the cove is just awesome for bringing in loaded boats.
It's only downfall is a very steep climb up what we call Mt. Poopashima. The privy is quite a climb up from the site.
Our 2nd favorite is Sandbanks, followed by Bur 2. We've stayed at some others but if it's available, Bur 1 is our go to.
The sites in the Narrows are great as well because of the shelter from any wind. And as said above they have good, sandy boat access.
To be fair, I have not camped many of the upper Richardson sites, but have visited quite a few. Some of them are definitely better suited to kayak access.