Every loop other than 1500 and 2000 are full hook up. With preferred you add cable. So, do you want/need cable?
There are 3 levels of campsites at Fort Wilderness:
Standard, which includes electric and water This includes the 1500 and 2000 loops
Full Hook Up, which includes electric, water and sewer (most of them are this way) This includes the 600, 800, 900, 1000, 1100, 1200, 1300, 1600, 1700, 1800, and 1900 loops.
Preferred, which includes electric, water, sewer and cable TV. As of the summer of 2005 high speed internet access was added to the preferred loops. via cable modems The preferred sites are also in loops situated closer to the settlement which includes the marina, beach, restaurant, and many other activities. Also, if you plan on using the cable TV hook up, remember to bring a long coaxial cable to hook up with. If you don't have one Disney will be happy to sell you one. The preferred loops include the 100, 200, 300, 400, 500, 700 and 1400 loops.
I have a loop map on my FW site, link below