Stone Mtn is nearly always busy, so your chances of getting any particular site # are slim. Many of the sites are relatively short and not all that level, so you may well encounter what ferfer did. However, your rig isn't real long and unlike a long motorhome, you can place the truck crosswise or whatever. I would suggest describing your rig as being larger, to try to get some room. Your 264BHW is considered a 26 footer, but its overall length is 29.5 ft, so make sure you call it 29 or 30 footer and not a 26. It might help get a larger spot. I think the premium spots are a bit roomier as well.
Hunting around for an alternative to the assigned site is worthwhile if you find the assigned site a poor match for you needs.