Hi Amy,
The campsites are a great way to stay at Disney, and, in my opinion, it is the best resort on property because it offers you an affordable way to stay while also having a feeling of "home" to it.
There are four categories of campsites at FW, premium, preferred, full-hookup, and partial.
The Premium Site is billed as "big-rig" friendly. They accommodate RVs larger than 45 feet in length and those that have multiple slide outs. The sites are wide (some up to 24 ft), and deeper (up to 60 ft) meaning they have a larger, level-paved pad. They also feature all of the amenities - water, power, sewer, and cable. Tent campers can use premium sites, but since they have a full pad with no sand area at all, unlike the preferred, full, and partial, it can be impossible to find a place to put in tent stakes. The actual size and shape of each site "will depend on Mother Nature", as Disney likes to say.
Preferred sites means those that are located near the Settlement Trading Post, Pioneer Hall, and marina areas. They have water, power, sewer, and cable.
The Full-Hookup sites are in loops 1600, 1700, 1800, and 1900 have all the hookups and a tent pad. Their location more or less not close to any of the main locations in the Fort, but they are very nice and I would have no problems staying on them.
Loops 1500 and 2000 are the partials and are great for tents and small campers and offer everything except for sewer.
Fort Wilderness also has an area called Creekside Meadow: it is a primitive campsite area and is usually used by boy scouts and other groups.
Here is a basic list of the sites and their category and if they are pet friendly or not.
Loop 100 - Preferred
Loop 200 - Preferred
Loop 300 - Preferred (Pet friendly loop)
Loop 400 - Premium (Pet friendly loop)
Loop 500 - Premium (Pet friendly loop)
Loop 600 - Premium (Pet friendly loop)
Loop 700 - Premium (Pet friendly loop)
Loop 800 - Premium (Pet friendly loop)
Loop 900 - Premium (Pet friendly loop)
Loop 1000 - Premium
Loop 1100 - Premium
Loop 1200 - Premium
Loop 1300 - Premium
Loop 1400 - Premium
Loop 1500 - Partial
Loop 1600 - Full (Pet friendly loop)
Loop 1700 - Full (Pet friendly loop)
Loop 1800 - Full (Pet friendly loop)
Loop 1900 - Full (Pet friendly loop)
Loop 2000 - Partial
Hope this helps