Most seasonal sites require that dogs be tied up, check the site rules to see if that's the case for you. We have a 30' cable that we keep ours on. It's plenty enough for him to run around and play.
2010 Jayco Eagle 351RLSA
2011 Nissan Titan 4x4 (don't worry, I don't pull the Eagle with it!)
Currently shopping for a Silverado 3500 Duramax
Oh, and I have a tent... Somewhere around here....