I know this is an old post but thought I'd follow up in case anyone else was wondering about the process.
I finally gave up trying to request a loop on the web site and had my better half call. We were able to request a loop but not a site over the phone.
When we arrived, we didn't get what we requested. Didn't matter much. All the sites were great. I walked all over and though some were nearer to attractions and/or amenities none were bad in my opinion.
People spent most of their day at the various Disney Parks so the campground itself was relatively quiet most of the time.
I love threads like this. Now to stir the pot.
I use a 220 volt appliance in my camper. It's a 4,000 watt heater I can't run it when hooked up to 30 amps but I can when I use 50 amp. I don't live in a cold part of the country but it's done the job down to 25 degrees during winter without having to use the furnace.
My camper was originally 30 amp but I converted it to 50 amp. Here's where you by the book guys will get upset. I use 10/4 wire with 50 amp plug and receptacle. Looks like 10/3 so it looks like I'm using 30 amps at the pedestal plus it's light weight and easy to handle. I installed a new electrical panel with a 30 amp main in the basement. I run all the factory electrical off one leg leaving me the second leg for additional appliances/devices. All additional circuits use properly sized wire and appropriate breakers for the load.
I can never draw more than 30 amps as determined by the new main breaker so 10/4 wire is adequate. My "exposure" is from the pedestal to my new panel. The possibility of a problem on that run is remote but admittedly not zero.
I wouldn't use 10/4 on a RV originally equipped with 50 amp service unless I was able to swap the main breaker down to 30 amps.