Don't even know if this is possible, but may be passing through that way in the next week to 10 days and was wondering what the difference in the the preferred and full-hook up sites? Is it maybe internet access?
Preferred sites do have the "sand pads" they are 100 to 300 loops and are located closest to the Marina and Settlement, thus "preferred location" but can be somewhat of a challenge to get a larger unit in. Full hook-up sites are 1600 to 1900 located closests to the main entrance to the Fort.
The premium sites have the larger concrete pad and no sand and are designed for "big rig" access.