I have seen many in the 700 loop also 900, 800. Just tell them to note on your reservation and they put you in a site for your rig..
Very good advice.
Some things to keep in mind when making a reservation at Fort Wilderness. The folks who answer the phone (i.e. reservations cast members) have differing levels of expertise regarding Fort Wilderness. Think about it, there are tens of thousands of Disney hotel rooms fitting into a few categories such as Value, Moderate and Deluxe and most rooms, no mater what property have similar size rooms, room capacities and rules regarding the room. So, the reservations cast members have most of the information regarding rooms in their head. Except for the exceptional reservations cast members, for Fort Wilderness they usually read what is on the screen in front of them. You may need to guide them with your reservation as you may actually know more about the campground then they do. At the very least, make sure they note the following things in the comments for your reservation:
Type of camping unit (i.e. trailer, tent, motorhome/coach etc.)
Length of your entire rig including tow vehicles and toads
Number/location of all awnings
Number/location of all slides
Let them know if you are bringing pets
Another thing I do is call back a few days after my original call and ask that they read me back the notes. If they have what I told them everything is good to go.
Now the other secret. After you drive through the check in lanes you start down a 2 lane road. There is a pull over/TOAD unhooking area just down this road. Unhook, and use your TAOD to go check out the site. If it's not good, drive around you loop or those of the same category (in your case Premium Pet) and pick a few sites you like. Drive the the closest comfort station and pick up the house phone and call the front desk. Tell them you site number and advise them you won't fit. Ask if they can reassign you to XXXX site (from your list). They can usually set you up over the phone and you are good to go. Again, it has to be the same category site. You can't reserve a tent site and ask to be reassigned to a premium
Now, if the place is packed/wall to wall campers it won't work as well, but it may help you out.