I would recommend calling FT W directly (They know more than central reservations). There usually is a max amount of people alllowed per site. Trust me this is for everyone's one good. They WILL enforce it if they see peeps are over occupying a site.
More than likely your number will be OK. Another option too if you want more room is they will get you adjoining campsites if you're interested.
Alot depends too on how much your party wants to 'use' the site for gathering. If you guys are into cooking out and chillin' outside your RV with a tent/RV you might not have as much room as you would like.
Also, if you have an additional vehicle that might get VERY tight. They strictly enforce keeping vehicles on their sites. Again, this is something one would appreciate when they stay there.
If you have any additional cars/towing stuff you can park it in the guarded parking alot. More than likely you will find the site OK size wise.